% This file was created with JabRef 2.3.1. % Encoding: ISO8859_1 @STRING{APL = {Appl. Phys. Lett.}} @STRING{POP = {Phys. Plasmas}} @STRING{PRL = {Phys. Rev. Lett.}} @STRING{RMP = {Rev. Mod. Phys.}} @ARTICLE{acedo_co2_2004, author = {Pablo Acedo and Horacio Lamela and Miguel Sanchez and Teresa Estrada and Joaquin Sanchez}, title = {CO2 (lambda[sub m] = 10.6 mu m) {He--Ne} (lambda[sub c] = 633 nm) two-color laser interferometry for low and medium electron density measurements in the {TJ-II} Stellarator}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, pages = {4671--4677}, number = {11}, month = nov, doi = {10.1063/1.1809283}, keywords = {plasma confinement,plasma radiofrequency heating,vibrations,CDX-U}, url = {http://link.aip.org/link/?RSI/75/4671/1} } @ARTICLE{adam_destabilization_1976, author = {J. C. Adam and W. M. Tang and P. H. Rutherford}, title = {Destabilization of the trapped-electron mode by magnetic curvature drift resonances}, journal = {Physics of Fluids}, year = {1976}, volume = {19}, pages = {561--566}, number = {4}, month = apr, doi = {10.1063/1.861489}, keywords = {trapped electron mode, CTEM, drift waves, trapped particles}, url = {http://link.aip.org/link/?PFL/19/561/1} } @ARTICLE{adelberger_solar_1998, author = {Eric G. Adelberger and Sam M. Austin and John N. Bahcall and A. B. Balantekin and Gilles Bogaert and Lowell S. Brown and Lothar Buchmann and F. Edward Cecil and Arthur E. Champagne and Ludwig de Braeckeleer and Charles A. Duba and Steven R. Elliott and Stuart J. Freedman and Moshe Gai and G. Goldring and Christopher R. Gould and Andrei Gruzinov and Wick C. Haxton and Karsten M. Heeger and Ernest Henley and Calvin W. Johnson and Marc Kamionkowski and Ralph W. Kavanagh and Steven E. Koonin and Kuniharu Kubodera and Karlheinz Langanke and Tohru Motobayashi}, title = {Solar fusion cross sections}, journal = {Reviews of Modern Physics}, year = {1998}, volume = {70}, pages = {1265}, month = oct, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, url = {http://link.aps.org/abstract/RMP/v70/p1265} } @ARTICLE{akiyama_co2_2003, author = {T. Akiyama and K. Tanaka and L. N. Vyacheslavov and A. Sanin and T. Tokuzawa and Y. Ito and S. {Tsuji-Iio} and S. Okajima and K. Kawahata}, title = {{CO2} laser imaging interferometer for high spatial resolution electron density profile measurements on {LHD}}, journal = {Papers from the 14th Topical Conference on High Temperature Plasma Diagnostics}, year = {2003}, volume = {74}, pages = {1638--1641}, month = mar, doi = {10.1063/1.1532759}, keywords = {carbon compounds, fusion reactor instrumentation, gas lasers, light interferometers, plasma density, plasma diagnostics, plasma toroidal confinement}, url = {http://link.aip.org/link/?RSI/74/1638/1} } @ARTICLE{allain_temperature_2003, author = {{J.P.} Allain and {M.D.} Coventry and {D.N.} Ruzic}, title = {Temperature dependence of liquid-lithium sputtering from oblique 700 {eV} He ions}, journal = {Journal of Nuclear Materials}, year = {2003}, volume = {313-316}, pages = {641--645}, month = mar, abstract = {The lithium-sputtering yield of liquid lithium as a function of sample temperature has been measured in the ion-surface interaction experiment {(IIAX).} Lithium sputtering is measured for D+, He+ and Li+ bombardment at energies between 100 and 1000 {eV} at 45° incidence. In this work {VFTRIM-3D} is used to provide a qualitative physical picture of mechanisms responsible for the temperature dependence of liquid-lithium sputtering. The present study is done for 700 {eV} He+ bombardment of liquid lithium at 45° incidence with respect to the target normal. The lithium-sputtering yield, after evaporation is taken into account, is found to increase almost an order of magnitude when the target temperature is increased from the melting point up to roughly 410 {°C.} The deposited energy distribution near the liquid-lithium surface is found to play a significant role in explaining the observed enhanced lithium sputtering as well as the temperature dependence of the surface binding energy.}, doi = {10.1016/S0022-3115(02)01371-5}, issn = {0022-3115}, keywords = {Evaporation, Liquid lithium, Plasma-wall interactions, Sputtering, Thermal sputtering, {VFTRIM-3D}}, url = {http://www.sciencedirect.com/science/article/B6TXN-47RRX95-C/2/d46de68dedf27beb041788741af1438a} } @ARTICLE{allain_liquid_lithium_studies_2004, author = {{J.P.} Allain and M. Nieto and {M.D.} Coventry and R. Stubbers and {D.N.} Ruzic}, title = {Studies of liquid-metal erosion and free surface flowing liquid lithium retention of helium at the University of Illinois}, journal = {Fusion Engineering and Design}, year = {2004}, volume = {72}, pages = {93--110}, number = {1-3}, month = nov, abstract = {The erosion of liquid-metals from low-energy particle bombardment at 45° incidence has been measured for a combination of species and target materials in the ion-surface interaction experiment {(IIAX)} at the University of Illinois {Urbana-Champaign.} Measurements include bombardment of liquid Li, {Sn-Li} and Sn by H+, D+, He+, and Li+ particles at energies from 100 to 1000 {eV} and temperatures from 20 to 420 {°C.} Lithium sputtering near and just above the melting point shows little change compared to room temperature, {solid-Li} yields. When lithium is sputtered, about 2/3 of the sputtered flux is in the charged state. Temperature-dependent sputtering results show enhanced (up to an order-of-magnitude increase) sputter yields as the temperature of the sample is increased about a factor of two of the melting point for all liquid-metals studied (e.g., Li, {Sn-Li,} and Sn). The enhancement is explained by two mechanisms: near-surface binding of eroded atoms and the nature of the near-surface recoil energy and angular distribution as a function of temperature. The Flowing Liquid Retention Experiment {(FLIRE)} measured particle transport by flowing liquid films when exposed to energetic particles. Measurements of retention coefficient were performed for helium ions implanted by an ion beam into flowing liquid lithium at 230 {°C} in the {FLIRE} facility. A linear dependence of the retention coefficient with implanted particle energy is found, given by the expression R = (5.3 ± 0.2) × 10-3 {keV-1.} The ion flux level did not have an effect for the flux level used in this work ({\textasciitilde}1013 cm-2 s-1) and square root dependence with velocity is also observed, which is in agreement with existing particle transport models.}, doi = {10.1016/j.fusengdes.2004.07.006}, issn = {0920-3796}, keywords = {Evaporation, {FLIRE,} Plasma}, url = {http://www.sciencedirect.com/science/article/B6V3C-4D8VMGD-1/2/07a16960cb59216ccf6937b21fa1109e} } @ARTICLE{allain_measurements_2002, author = {{J.P.} Allain and {D.N.} Ruzic}, title = {Measurements and modelling of solid phase lithium sputtering}, journal = {Nuclear Fusion}, year = {2002}, volume = {42}, pages = {202--210}, number = {2}, abstract = {The absolute sputtering yields of D+, He+ and Li+ on deuterium saturated solid lithium have been measured and modelled at 45deg incidence in the energy range 100-1000 {eV.} The Ion-surface {InterAction} Experiment {(IIAX)} was used to measure the absolute sputtering yield of lithium in the solid phase from bombardment with a Colutron ion source. The lithium sample was treated with a deuterium plasma from a hollow cathode source. Measurements also include bombardment of non-deuterium-saturated lithium surfaces. The results lead to the conclusion that the chemical state of the deuterium treated lithium surface plays a major role in the decrease of the lithium sputtering yield. Specifically, preferential sputtering of implanted deuterium atoms over lithium atoms in deuterium treated samples results in a decrease of at least 60\% of the lithium sputtering yield, in the case of He+ bombardment. These results also demonstrate that lithium self-sputtering is well below unity and that the fraction of sputtered species in an ionic state ranges from 55 to 65\% for incident particle energies between 100 and 1000 {eV.} Furthermore, correlation of Monte Carlo {VFTRIM-3D} simulations and {IIAX} experimental data demonstrate that the surface composition has a one to one ratio between deuterium and lithium components.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/42/2/312} } @ARTICLE{allain_lithium_2004, author = {{J.P.} Allain and {D.G.} Whyte and {J.N.} Brooks}, title = {Lithium erosion experiments and modelling under quiescent plasma conditions in {DIII-D}}, journal = {Nuclear Fusion}, year = {2004}, volume = {44}, pages = {655--664}, number = {5}, abstract = {Lithium-sputtering erosion and transport has been measured in the outer divertor of the {DIII-D} tokamak. The Divertor Materials Evaluation System {(DiMES)} mechanism places a 2.5 cm lithium spot as a plasma-facing surface in the divertor. Plasma diagnostics and atomic lithium visible spectroscopy are used to measure the lithium erosion yield near the outer strikepoint {(OSP)} with swept-plasma parameters of electron temperature 5-25 {eV} and electron density (0.03-1.80) x 1019 m[?]3. Solid-phase lithium physical sputtering is measured to be less than 10\% {(Li/D+).} The yield increases with incident energy. Physical sputtering models confirm measurements of sputtered energy and spatial distributions showing skewed angular distributions when the sample is exposed near the {OSP} and isotropic angular distributions when the sample is exposed to the private flux region. {REDEP/WBC} modelling of near-surface impurity transport agrees well with experimental measurements showing sputtered lithium neutral atoms effectively ionized about a centimetre away from the {Li-DiMES} probe surface. A reduction in lithium physical sputtering by a factor of 4-5 is measured when the lithium surface forms an oxide, consistent with the physical sputtering behaviour of most metal-oxides. Although of less significance than lithium atom transport, there is a modelling/data discrepancy regarding lithium ion transport with, e.g. the data showing more asymmetric ion transport than predicted.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/44/5/009} } @CONFERENCE{allis2005, author = {Michelle K. Allis and Nicolas Gascon and Mark A. Cappelli}, title = {Effect of Charge Exchange on 2D Hall Thruster Simulation}, booktitle = {IEPC-2005-057}, year = {2005}, publisher = {IEPC}, journal = {Journal of Applied Physics}, keywords = {atom-ion collisions; charge exchange; xenon; Hall thruster, simulation, 1yr_project}, timestamp = {2007.10.19}, url = {http://www.stanford.edu/group/pdl/Papers/2005/Allis-IEPC-2005-057.pdf} } @ARTICLE{angelopoulos_tail_2008, author = {Vassilis Angelopoulos and James P. McFadden and Davin Larson and Charles W. Carlson and Stephen B. Mende and Harald Frey and Tai Phan and David G. Sibeck and Karl-Heinz Glassmeier and Uli Auster and Eric Donovan and Ian R. Mann and I. Jonathan Rae and Christopher T. Russell and Andrei Runov and Xu-Zhi Zhou and Larry Kepko}, title = {Tail Reconnection Triggering Substorm Onset}, journal = {Science}, year = {2008}, pages = {1160495}, month = jul, abstract = {Magnetospheric substorms explosively release solar wind energy previously stored in Earth's magnetotail, encompassing the entire magnetosphere and producing spectacular auroral displays. It has been unclear whether a substorm is triggered by a disruption of the electrical current flowing across the near-Earth magnetotail, at \~10 RE (RE = Earth Radius, or 6374 km), or by the process of magnetic reconnection typically seen farther out in the magnetotail, at \~20 to 30 RE. We report on simultaneous measurements in the magnetotail at multiple distances, at the time of substorm onset. Reconnection was observed at 20 RE, at least 1.5 min before auroral intensification, at least 2 min before near-Earth current disruption, and about 3 min before substorm expansion. These results demonstrate that substorms are likely initiated by tail reconnection. }, doi = {10.1126/science.1160495}, url = {http://www.sciencemag.org/cgi/content/abstract/1160495v1} } @ARTICLE{antar_plasma-lithium_2002, author = {G. Y. Antar and R. P. Doerner and R. Kaita and R. Majeski and J. Spaleta and T. Munsat and B. Jones and R. Maingi and V. Soukhanovskii and H. Kugel and J. Timberlake and S. I. Krasheninnikov and S. C. Luckhardt and R. W. Conn}, title = {Plasma-lithium interaction in the {CDX-U} spherical torus}, journal = {Fusion Engineering and Design}, year = {2002}, volume = {60}, pages = {157--166}, number = {2}, month = may, abstract = {Results on the interaction between plasma in the current drive experiment-upgrade {(CDX-U)} spherical torus and a liquid lithium limiter are reported. It is observed that macroscopic lithium droplets detach from the limiter head and fall towards the plasma core. However, no disruptions occurred during these discharges despite the fact that relatively large-scale blobs are observed entering the confined plasma. A multi-tip Langmuir probe measures the edge plasma properties. It is found that the average density and temperature and their fluctuations are unaffected by the presence of lithium within experimental error.}, doi = {10.1016/S0920-3796(02)00055-8}, issn = {0920-3796}, keywords = {CDX-U,Lithium walls,MHD effects,Plasma-material interaction}, url = {http://www.sciencedirect.com/science/article/B6V3C-45H0BY8-1/2/dab64e1a1d7c40becf57fd6d68c7f710} } @ARTICLE{arslanbekov_modeling_1998, author = {Robert R. Arslanbekov and Anatoly A. Kudryavtsev}, title = {Modeling of nonlocal electron kinetics in a low-pressure afterglow plasma}, journal = {Physical Review E}, year = {1998}, volume = {58}, pages = {7785}, month = dec, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {The electron kinetics in a low-pressure afterglow plasma is studied by means of the time- and space-dependent Boltzmann (kinetic) equation. A method based on the nonlocal approach is presented, which enables the nonlocal nature of the electron distribution function (EDF) to be accounted for in a simple manner, without solving a complicated kinetic equation. Simplified kinetic equations are derived, as well as some analytic solutions, for obtaining the EDF in terms of its energy-averaged parameters, such as the electron density and temperature. This allows an energy-balance equation to be used to describe the electron-energy decay at the kinetic level. To validate the proposed method, the full time- and space-dependent kinetic equation is solved numerically for an afterglow in Ar. It is observed that under nonlocal conditions the EDF is strongly non-Maxwellian. As a consequence, the values of the wall potential predicted using the kinetic approach differ drastically from those obtained on the premise of a Maxwellian EDF. Another striking nonlocal effect manifests itself in a strong spatial inhomogeneity of the electron temperature. The derived energy-balance equation coupled with the simplified nonlocal kinetic equations reproduce accurately both the spatial profiles and absolute values of the electron temperature obtained from the full kinetic simulations. An interesting phenomenon, obtained numerically and explained in terms of the nonlocal EDF, is that the radial fluxes of different portions of the EDF have opposite directions. A direct comparison between the fluid and kinetic approaches is carried out, and it is concluded that the fluid approach fails to describe correctly the essential properties of a low-pressure afterglow plasma, such as the temporal and spatial evolution of the electron temperature. It is further demonstrated that the volume-averaged (zero-dimensional) kinetic models can also lead to erroneous results in describing such plasmas. It is shown that superthermal electrons produced in processes involving metastables can have a great influence on the plasma decay, particularly on the wall potential and the diffusion-cooling rate. The present method has the advantage of being simple and semianalytic, and thus can be very useful in solving complex self-consistent problems.}, doi = {10.1103/PhysRevE.58.7785}, url = {http://link.aps.org/abstract/PRE/v58/p7785} } @ARTICLE{arslanbekov_electron-distribution-function_2001, author = {Robert R. Arslanbekov and Anatoly A. Kudryavtsev and Lev D. Tsendin}, title = {Electron-distribution-function cutoff mechanism in a low-pressure afterglow plasma}, journal = {Physical Review E}, year = {2001}, volume = {64}, pages = {016401}, month = jun, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {A model is developed for self-consistent simulations of transient phenomena in a low-pressure afterglow plasma. The model is based on the nonlocal approach which allows a kinetic description of the plasma decay under nonquasistationary conditions. Such conditions arise when collisions (mainly electron-electron) are not sufficient for the electron distribution function (EDF) to follow changes in the self-consistent electric fields and the ion density once the power is turned off. As a result, collisions cannot provide the electron and ion particle balance by allowing electrons to flow out of the potential well. A cutoff mechanism is suggested that provides such a balance during the transient period?from the glow, stationary plasma to the quasistationary, afterglow plasma. This mechanism is essential for determining correctly the self-consistent wall potential (and hence the energy of ions impinging upon the wall surface) and other parameters, such as diffusion cooling, which is the most important cooling mechanism at low pressures. These phenomena are modeled using the time-dependent nonlocal electron Boltzmann equation with a nonlinear electron-electron collision operator. A numerical treatment is made by extending Rockwood?s method for finite-difference discretization of this operator in the total energy formulation. The model calculates self-consistently the temporal evolution of the nonlocal EDF and the electric potentials in the plasma and the wall sheath. Strongly non-Maxwellian EDF?s are predicted and it is observed that, depending on plasma conditions, the transient period maybe rather long, of order of the ambipolar diffusion time, lower pressures resulting in longer transient times. The proposed approach can be applied to model self-consistently pulsed plasmas during both the power-on and power-off periods, including the breakdown period.}, doi = {10.1103/PhysRevE.64.016401}, url = {http://link.aps.org/abstract/PRE/v64/e016401} } @ARTICLE{1998PhRvE..58.7785A, author = {{Arslanbekov}, R.~R. and {Kudryavtsev}, A.~A.}, title = {Modeling of nonlocal electron kinetics in a low-pressure afterglow plasma}, journal = {\pre}, year = {1998}, volume = {58}, pages = {7785-7798}, month = dec, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1998PhRvE..58.7785A}, doi = {10.1103/PhysRevE.58.7785}, keywords = {nonlocal, 2yr_project} } @ARTICLE{atipo2002, author = {Atipo, A. and Bonhomme, G. and Pierre, T}, title = {Ionization waves: from stability to chaos and turbulence}, journal = {European Physical Journal D}, year = {2002}, volume = {19}, pages = {79-87}, note = {Uses photodetectors to collect ionization wave light intensity, then the method of Biorthogonal Decomposition (standing-wave wavefuntions which are generated from the data, ie. not fourier series) to measure the spatio-temporal complexity. Found regimes of regular and chaotic behavior. Several routes to chaos were identified: sub-harmonic cascade (f/3 and 2f/3), Ruelle, Takens, Newhouse scenario (quasi-periodic state from two interacting modes w/ non-equal frequencies), and period doubling (in a short discharge). Also discusses transition from compact (short discharge) to extended (long discharge) dynamical system.}, keywords = {Plasma lab class, chaos, biorthogonal decomposition, chaotic transition, ionization waves, glow discharge, plasma_lab}, owner = {egranste}, timestamp = {2007.04.20} } @INPROCEEDINGS{azziz_plume_measurements_2004, author = {Yassir Azziz and Noah Z. Warner and Manuel Mart\'inez-S\'anchez}, title = {High Voltage Plume Measurements and Internal Probing of the BHT-1000 Hall Thruster}, booktitle = {40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit}, year = {2004}, series = {AIAA paper no. 2004-4097}, address = {Fort Lauderdale, Florida}, month = {JUL}, keywords = {Hall thruster, 1yr\_project, plume}, owner = {erikg}, timestamp = {2008.04.01}, url = {http://www.aiaa.org/content.cfm?pageid=413} } @ARTICLE{baldwin_plasma_2002, author = {M. J. Baldwin and R. P. Doerner and S. C. Luckhardt and R. Seraydarian and D. G. Whyte and R. W. Conn}, title = {Plasma interaction with liquid lithium: Measurements of retention and erosion}, journal = {Fusion Engineering and Design}, year = {2002}, volume = {61-62}, pages = {231--236}, month = nov, abstract = {This paper reports on recent studies of high flux deuterium and helium plasma interaction with liquid lithium in the {Pisces-B} edge plasma simulator facility. Deuterium retention is explored as a function of plasma ion fluence in the range 6×1019-4×1022 atoms cm-2 and exposure temperatures of 523-673 K. The results are consistent with full uptake of the deuterium ions incident on the liquid metal surface, independent of the temperature of the liquid lithium. Full uptake continues until the sample is volumetrically converted to lithium deuteride. Helium retention is not observed for fluences up to 5×1021 He atoms cm-2. Measurements of the erosion of lithium are found to be consistent with physical sputtering for the lithium solid phase. However, a mechanism that provides an increased evaporative-like yield and is related to ion impact events on the surface, dominates during the liquid phase leading to an enhanced loss rate for liquid lithium that is greater than the expected loss rate due to evaporation at elevated temperatures. Further, the material loss rate is found to depend linearly on the incident ion flux, even at very high temperature.}, doi = {10.1016/S0920-3796(02)00232-6}, issn = {0920-3796}, keywords = {Erosion, Liquid lithium, Lithium deuteride, {Pisces-B,} Plasma facing materials, Retention, Sputtering, Thermal desorption spectrometry}, shorttitle = {Plasma interaction with liquid lithium}, url = {http://www.sciencedirect.com/science/article/B6V3C-47905XF-5/2/8c25a23b29a86baaf012e5539aa811fe} } @ARTICLE{baldwin_deuterium_2002, author = {{M.J.} Baldwin and {R.P.} Doerner and {S.C.} Luckhardt and {R.W.} Conn}, title = {Deuterium retention in liquid lithium}, journal = {Nuclear Fusion}, year = {2002}, volume = {42}, pages = {1318--1323}, number = {11}, abstract = {Measurements of deuterium retention in samples of lithium exposed in the liquid state to deuterium plasma are reported. Retention was measured as a function of plasma ion dose in the range 6x1019-4x1022 D atoms and exposure temperature between 523 and 673 K using thermal desorption spectrometry. The results are consistent with the full uptake of all deuterium ions incident on the liquid metal surface and are found to be independent of the temperature of the liquid lithium over the range explored. Full uptake, consistent with very low recycling, continues until the sample is volumetrically converted to lithium deuteride. This occurs for exposure temperatures where the gas pressure during exposure was both below and slightly above the corresponding decomposition pressure for {LiD} in Li.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/42/11/305} } @ARTICLE{boeuf2004, author = {Bareilles, J. and Hagelaar, G.J.M. and Garrigues, L., and Boniface, C. and Boeuf, J.P}, title = {Critical assessment of a two-dimensional hybrid Hall thruster model: Comparisons with experiments}, journal = {Physics of Plasmas}, year = {2004}, volume = {11}, pages = {3035-3046}, number = {6}, abstract = {A discussion is presented on the results and predictive capabilities of a two-dimensional (2D) hybrid Hall effect thruster (HET) model. It is well known that classical (collision-induced) cross-field electron transport and energy losses are not sufficient to explain the observed HET characteristics. The 2D, quasineutral, hybrid discharge model uses empirical parameters to describe additional, anomalous electron transport and energy loss phenomena. It is shown that, for properly adjusted empirical parameters, the model can qualitatively reproduce the observed thruster behavior over a large range of operating conditions. The ionization and transit-time oscillations predicted by the model are described, and their consequences on the time-averaged thruster properties are discussed. Finally, the influence of the empirical parameters on the model results is shown, especially on quantities that can be measured experimentally.}, keywords = {Hall Thruster, nsf_app, 1yr_project}, owner = {egranste}, timestamp = {2007.05.10} } @PHDTHESIS{beer_gyrofluid_1994, author = {Michael Beer}, title = {Gyrofluid Model of Turbulent Transport in Tokamaks}, school = {Princeton University}, year = {1994}, abstract = {Microinstability driven turbulence in tokamaks is studied via numerical simulation of a comprehensive fluid model. For the ions, toroidal gyrofluid equations are derived which contain accurate models of the kinetic effects arising from toroidal grad B and curvature drifts, parallel Landau damping and its inverse, finite Larmor radius effects, and trapped ion effects. For the electrons, sophisticated bounce averaged trapped electron fluid equations are derived which model the toroidal precession resonance and use a Lorentz collision operator for pitch angle scattering. These coupled ion and electron equations can simultaneously describe the nonlinear evolution of toroidal ion temperature gradient driven instabilities and trapped electron modes, and provide realistic nonlinear calculations of ion and electron heat fluxes and particle fluxes. These equations are solved in a reduced flux tube geometry, formulated in general magnetic coordinates. This technique exploits the elongated nature of microinstability driven turbulence, which has long parallel scales and short perpendicular scales. The reduced simulation volume allows high resolution simulations in realistic tokamak geometry, fully retaining important toroidal effects such as good and bad curvature. These toroidal simulations predict much larger thermal transport than found in simplified sheared slab geometry, bringing the predictions up to experimentally measured levels. The turbulent fluctuation spectrum is peaked at long wavelengths compared to the fastest growing linear modes, and the fluctuation spectrum is anisotropic in $k_r$ and $k_theta$, as seen in experimental fluctuation measurements. The nonlinear generation of sheared $E\times B$ flows is found to play an important role in the development and saturation of this turbulence, and the damping of these flows is carefully investigated. Finally, the predicted transport from these simulations is compared with experiment. The simulations underestimate the transport near the plasma edge, but encouraging agreement is found between the predicted and measured ion and electron heat transport in the core.}, file = {beer_gyrofluid_1994.pdf:refs/theses/beer_gyrofluid_1994.pdf:PDF}, keywords = {gyrokinetic, simulation}, owner = {erikg}, timestamp = {2009.07.14}, url = {http://w3.pppl.gov/~hammett/collaborators/mbeer/afs/thesis.html} } @INPROCEEDINGS{beer_gyrofluid_1997, author = {M. A. Beer and G. W. Hammett and G. Rewoldt and E. J. Synakowski and M. C. Zarnstorff and W. Dorland}, title = {Gyrofluid simulations of turbulence suppression in reversed-shear experiments on the Tokamak Fusion Test Reactor}, booktitle = {The 38th annual meeting of the Division of Plasma Physics (DPP) of the American Physical Society}, year = {1997}, volume = {4}, pages = {1792-1799}, address = {Denver, Colorado (USA)}, month = may, publisher = {AIP}, doi = {10.1063/1.872279}, journal = {The 38th annual meeting of the Division of Plasma Physics (DPP) of the American Physical Society}, keywords = {INSTABILITY GROWTH RATES,PLASMA CONFINEMENT,PLASMA FLUID EQUATIONS,PLASMA INSTABILITY,plasma kinetic theory,PLASMA SIMULATION,plasma toroidal confinement,plasma turbulence,TFTR TOKAMAK,TRAPPED ELECTRONS,TURBULENCE}, url = {http://link.aip.org/link/?PHP/4/1792/1} } @ARTICLE{bell_signal_1993, author = {J. D. Bell and J. H. Harris and J. L. Dunlap and N. A. Crocker and V. K. Pare}, title = {Signal analysis of fluctuations in toroidal fusion plasmas}, journal = {Review of Scientific Instruments}, year = {1993}, volume = {64}, pages = {2428--2433}, number = {9}, doi = {10.1063/1.1143900}, keywords = {ATF TORSATRON,FLUCTUATIONS,PLASMA,PLASMA DIAGNOSTICS,SIGNAL PROCESSING,SIGNALS}, url = {http://link.aip.org/link/?RSI/64/2428/1} } @ARTICLE{bell_new_2006, author = {{M.G.} Bell and {R.E.} Bell and {D.A.} Gates and {S.M.} Kaye and H. Kugel and {B.P.} {LeBlanc} and {F.M.} Levinton and R. Maingi and {J.E.} Menard and R. Raman and {S.A.} Sabbagh and D. Stutman and the {NSTX} Research Team}, title = {New capabilities and results for the National Spherical Torus Experiment}, journal = {Nuclear Fusion}, year = {2006}, volume = {46}, pages = {S565--S572}, number = {8}, note = {reversed shear}, abstract = {The National Spherical Torus Experiment (NSTX) produces plasmas with toroidal aspect ratio as low as 1.25, which can be heated by up to 6 MW high-harmonic fast waves and up to 7 MW of deuterium neutral beam injection. Using new poloidal field coils, plasmas with cross-section elongation up to 2.7, triangularity 0.8, plasma currents Ip up to 1.5 MA and normalized currents Ip/aBT up to 7.5 MA/m*T have been achieved. A significant extension of the plasma pulse length, to 1.5 s at a plasma current of 0.7 MA, has been achieved by exploiting the bootstrap and NBI-driven currents to reduce the dissipation of poloidal flux. Inductive plasma startup has been supplemented by coaxial helicity injection (CHI) and the production of persistent current on closed flux surfaces by CHI has now been demonstrated in NSTX. The plasma response to magnetic field perturbations with toroidal mode numbers n = 1 or 3 and the effects on the plasma rotation have been investigated using three pairs of coils outside the vacuum vessel. Recent studies of both MHD stability and of transport benefitted from improved diagnostics, including measurements of the internal poloidal field using the motional Stark effect (MSE). In plasmas with a region of reversed magnetic shear in the core, now confirmed by the MSE data, improved electron confinement has been observed.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/46/8/S01/} } @ARTICLE{berkery2007, author = {John W. Berkery and Thomas Sunn Pedersen and Jason P. Kremer and Quinn R. Marksteiner and Remi G. Lefrancois and Michael S. Hahn and Paul W. Brenner}, title = {Confinement of pure electron plasmas in the Columbia Non-neutral Torus}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {062503}, number = {6}, eid = {062503}, abstract = {The Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois, Q. Marksteiner, N. Pomphrey, W. Reiersen, F. Dahlgreen, and X. Sarasola, Fusion Sci. Technol. 50, 372 (2006)] is a stellarator used to study non-neutral plasmas confined on magnetic surfaces. A detailed experimental study of confinement of pure electron plasmas in CNT is described here. Electrons are introduced into the magnetic surfaces by placing a biased thermionic emitter on the magnetic axis. As reported previously, the insulated rods holding this and other emitter filaments contribute to the radial transport by charging up negatively and creating EB convective transport cells. A model for the rod-driven transport is presented and compared to the measured transport rates under a number of different conditions, finding good agreement. Neutrals also drive transport, and by varying the neutral pressure in the experiment, the effects of rod-driven and neutral-driven transport are separated. The neutral-driven electron loss rate scales linearly with neutral pressure. The neutral driven transport, presumably caused by electron-neutral collisions, is much greater than theoretical estimates for neoclassical diffusion in a classical stellarator with strong radial electric fields. In fact the confinement time is on the order of the electron-neutral collision time. Ion accumulation, electron attachment, and other effects are considered, but do not explain the observed transport rates. }, doi = {10.1063/1.2745814}, keywords = {stellarators; plasma toroidal confinement; plasma transport processes; plasma pressure; plasma collision processes}, numpages = {8}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/14/062503/1} } @INPROCEEDINGS{berzak_magnetic_2008, author = {L. Berzak and R. Kaita and T. Kozub and R. Majeski and L. Zakharov}, title = {Magnetic diagnostics for the lithium tokamak experiment}, booktitle = {PROCEEDINGS OF THE 17TH TOPICAL CONFERENCE ON HIGH-TEMPERATURE PLASMA DIAGNOSTICS}, year = {2008}, volume = {79}, pages = {10F116--3}, address = {Albuquerque, New Mexico {(USA)}}, month = oct, publisher = {AIP}, doi = {10.1063/1.2955567}, keywords = {coils,lithium,ltx,plasma confinement,plasma diagnostics,plasma flow,plasma heating,plasma materials processing,plasma transport {processes,Tokamak} devices}, url = {http://link.aip.org/link/?RSI/79/10F116/1} } @ARTICLE{biglari_influence_1990, author = {H. Biglari and P. H. Diamond and P. W. Terry}, title = {Influence of sheared poloidal rotation on edge turbulence}, journal = {Physics of Fluids B: Plasma Physics}, year = {1990}, volume = {2}, pages = {1-4}, doi = {10.1063/1.859529}, keywords = {ACCELERATION,DRIFT WAVES,ELECTRIC FIELDS,END EFFECTS,FLUCTUATIONS,INHIBITION,PLASMA,PLASMA DRIFT,SHEAR,TOKAMAK DEVICES,TURBULENCE}, url = {http://link.aip.org/link/?PFB/2/1/1} } @ARTICLE{block78, author = {L.P. Block}, title = {A double layer review}, journal = {Astrophysics and Space Science}, year = {1978}, volume = {55}, pages = {59-83}, file = {\\Docs\\Double Layers\\block78.pdf:\\Docs\\Double Layers\\block78.pdf:PDF}, keywords = {double layers, 1yr_project} } @ARTICLE{boedoshear2000, author = {Boedo, J. A. and Terry, P. W. and Gray, D. and Ivanov, R. S. and Conn, R. W. and Jachmich, S. and Van Oost, G. and The TEXTOR Team}, title = {Suppression of Temperature Fluctuations and Energy Barrier Generation by Velocity Shear}, journal = {Phys. Rev. Lett.}, year = {2000}, volume = {84}, pages = {2630--2633}, number = {12}, month = {Mar}, note = {Reporting measurements quantifying temperature and density fluctuations in a transport barrier. In simulations, suppression is achieved when the shearing rate $ \omega_{E\cross B} = dV_{E\cross B}/dr $ is of the order of the linear growth rate of the dominant instability mode of the plasma. Previous theoretical works (ref 9) that if parallel thermal conduction is high, flow shear can reduce particle flux, but have little effect on the heat flux. In experiments on TEXTOR, $E_r$ was applied with a graphite electrode inserted inside the last closed flux surface (LCFS), and biased positive. A radial electric field increases with voltage until a bifurcation occurs, with a maximum field of 500 V/cm. In this experiment, radiation from the graphite electrode reduces temperature inside the barrier by a factor of 2. They use a fast reciprocating array to measure $V_f$, $n$, and also poloidal and radial electric fields (how?). Temperature fluctuations are measured using the harmonics technique (ref 12). Consistent with the theory predictions, when parallel thermal conductivity is larger than the grouth rate, nonlinear decorrelation rate, or max value of the shear flow term, increases of the shear flow do not affect temperature fluctuations much; but if the shearing rate is the larges term, than temperature fluctuations should be suppresed. An upper limit on the heat flux is determined by assuming temperature and poloidal field fluctuations are strongly correlated (which has been shown experimentally); both the anomalous conducted and convected heat flux across the shear layer is reduced, with the conduction dominating the L-mode discharges by a factor of 7-10. Quenching this gives the energy barrier. Density fluctuations in H-mode are sensitive to higher derivatives of velocity, and therefore the first and second derivatives of the radial electric field. In computing a power balance, it is found that anomalous transport accounts for the power balance in L mode, but not in H mode conditions; ie. unknown sources are important. If only a particle barrier had been formed, the heat flux reduction would not have decreased as much.}, doi = {10.1103/PhysRevLett.84.2630}, numpages = {3}, publisher = {American Physical Society} } @INPROCEEDINGS{1958IAUS....6...87B, author = {{Bostick}, W.~H.}, title = {Experimental Study of Plasmoids}, booktitle = {Electromagnetic Phenomena in Cosmical Physics}, year = {1958}, editor = {{Lehnert}, B.}, volume = {6}, series = {IAU Symposium}, pages = {87-+}, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1958IAUS....6...87B} } @ARTICLE{bourdelle_stabilizing_2003, author = {C. Bourdelle and W. Dorland and X. Garbet and G. W. Hammett and M. Kotschenreuther and G. Rewoldt and E. J. Synakowski}, title = {Stabilizing impact of high gradient of beta on microturbulence}, journal = {Physics of Plasmas}, year = {2003}, volume = {10}, pages = {2881--2887}, number = {7}, month = jul, doi = {10.1063/1.1585032}, keywords = {plasma density, plasma instability, plasma temperature, plasma toroidal confinement, plasma turbulence}, url = {http://link.aip.org/link/?PHP/10/2881/1} } @ARTICLE{bourdelle_stabilizing_2003-1, author = {C. Bourdelle and W. Dorland and X. Garbet and G. W. Hammett and M. Kotschenreuther and G. Rewoldt and E. J. Synakowski}, title = {Stabilizing impact of high gradient of beta on microturbulence}, journal = {Physics of Plasmas}, year = {2003}, volume = {10}, pages = {2881--2887}, number = {7}, month = jul, doi = {10.1063/1.1585032}, keywords = {plasma density, plasma instability, plasma temperature, plasma toroidal confinement, plasma turbulence}, url = {http://link.aip.org/link/?PHP/10/2881/1} } @BOOK{boxman_raymond_l_handbook_1995, title = {Handbook of vacuum arc science and technology}, publisher = {Noyes Publications}, year = {1995}, author = {Boxman, Raymond L.}, pages = {742}, series = {Materials science and process technology series. Electronic materials and process technology}, address = {Park Ridge, NJ}, keywords = {cathode,filament,thermionic emission,vacuum, 1yr_project}, url = {http://www.knovel.com/knovel2/Toc.jsp?BookID=138} } @ARTICLE{breslau_three-dimensional_2007, author = {J. A. Breslau and S. C. Jardin and W. Park}, title = {Three-dimensional modeling of the sawtooth instability in a small tokamak}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {056105--7}, number = {5}, month = may, doi = {10.1063/1.2695868}, keywords = {magnetic reconnection, plasma magnetohydrodynamics, plasma nonlinear processes, plasma simulation, plasma toroidal confinement, sawtooth instability, stochastic processes, Tokamak devices}, url = {http://link.aip.org/link/?PHP/14/056105/1} } @ARTICLE{breslau_improved_2008, author = { {JA} Breslau and {CR} Sovinec and {SC} Jardin}, title = {An improved tokamak sawtooth benchmark for {3D} nonlinear {MHD}}, journal = {{COMMUNICATIONS} {IN} {COMPUTATIONAL} {PHYSICS}}, year = {2008}, volume = {4}, pages = {647--658}, number = {3}, month = sep, abstract = {Accurate prediction of the sawtooth cycle [1] is an important test for nonlinear {MHD} codes. The sawtooth cycle in the {CDX-U} tokamak [2], chosen because its small size and low temperature allow simulation using actual device parameters, has been an important benchmark for the comparison of the {M3D} [3] and {NIMROD} [5] codes for the last several years. Successive comparisons have led to improvements and refinements in both codes. The most recent comparisons show impressive agreement between the two codes both on the linear instability and on the details of nonlinear cyclical behavior. These tests are somewhat idealized and do not yet agree quantitatively with the experimentally observed sawtooth period. We expect a second generation of {CDX-U} sawtooth benchmarks based on an analytically specified equilibrium, with source terms that show greater fidelity to the physical device, to produce better agreement.}, issn = {1815-2406}, url = {http://www.global-sci.com/issue/abstract/readabs.php?vol=4&page=659} } @ARTICLE{brooks_psi_2005, author = {J.N. Brooks and J.P. Allain and T.D. Rognlien and R. Maingi}, title = {PSI modeling of liquid lithium divertors for the NSTX tokamak}, journal = {Journal of Nuclear Materials}, year = {2005}, volume = {337-339}, pages = {1053-1057}, month = mar, abstract = {We analyzed plasma surface interaction issues for the planned Module-A static liquid lithium divertor for NSTX using coupled codes/models describing the plasma edge, divertor temperature, and erosion/redeposition, with input data from tokamak and laboratory experiments. A 300?nm lithium pre-shot deposited coating will strongly pump impinging D+ ions. This yields a low-recycle SOL plasma with high plasma temperature, Te?\~?200-400?eV, low density, Ne?\~?1-3??1018?m-3, and peak heat loads of \~8-20?MW/m2, for 2-4?MW core plasma heating power. This regime has advantages for the NSTX physics mission. Peak surface temperature can be held to an acceptable [less-than-or-equals, slant]470??C with moderate strike point sweeping (10?cm/s) using a carbon (for 2?MW) or Mo/Cu or W/Cu substrate (2-4?MW). Erosion/redeposition analysis shows acceptable coating lifetime for a 2?s pulse and low core plasma contamination by sputtered lithium.}, doi = {10.1016/j.jnucmat.2004.07.062}, keywords = {Density control,Divertor modeling,Erosion/redeposition,Lithium,NSTX,recycling}, url = {http://www.sciencedirect.com/science/article/B6TXN-4FB9GYJ-V/2/0536b6322d7fd1b62fcec38aaf01319d} } @ARTICLE{brower_fizeau_2004, author = {D. L. Brower and W. X. Ding and B. H. Deng and M. A. Mahdavi and V. Mirnov and S. C. Prager}, title = {Fizeau interferometer for measurement of plasma electron current}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, pages = {3399}, number = {10}, doi = {10.1063/1.1780771}, issn = {00346748}, url = {http://link.aip.org/link/RSINAK/v75/i10/p3399/s1&Agg=doi} } @ARTICLE{bugrova1999, author = {Bugrova, A.I. and Lipatov, A.S. and Morozov, A.I and Kharchevnikov, V.K}, title = {Membrane oscillations in the channel of a steady-state plasma thruster}, journal = {Plasma Physics Technical Physics}, year = {1999}, volume = {25}, pages = {64-68}, abstract = {Extremely strong low-frequency oscillations (;35 kHz) predicted earlier were observed experimentally in the channel of a steady-state plasma thruster. These oscillations are mainly caused by fluctuations of the electron temperature and affect the ion beam divergence.}, keywords = {nsf_app, Hall thruster, 1yr_project}, owner = {egranste}, timestamp = {2007.05.10} } @ARTICLE{burin_transition_2005, author = {M. J. Burin and G. R. Tynan and G. Y. Antar and N. A. Crocker and C. Holland}, title = {On the transition to drift turbulence in a magnetized plasma column}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {052320--14}, number = {5}, month = may, doi = {10.1063/1.1889443}, keywords = {argon,dispersion relations,plasma density,plasma drift waves,plasma flow,plasma fluctuations,plasma nonlinear processes,plasma transport processes,plasma turbulence}, url = {http://link.aip.org/link/?PHP/12/052320/1} } @INPROCEEDINGS{thomas_direct_2003, author = {C. E. (Tommy) Thomas, Jr. and Martin A. Hunt and Tracy M. Bahm and Larry R. Baylor and Philip R. Bingham and Matthew D. Chidley and Xiaolong Dai and Robert J. Delahanty and Ayman El-Khashab and Judd M. Gilbert and James S. Goddard and Gregory R. Hanson and Joel D. Hickson and Kathy W. Hylton and George C. John and Michael L. Jones and Michael W. Mayo and Christopher Marek and John H. Price and David A. Rasmussen and Louis J. Schaefer and Mark A. Schulze and Bichuan Shen and Randall G. Smith and Allen N. Su and Kenneth W. Tobin and William R. Usry and Edgar Voelkl and Karsten S. Weber and Robert W. Owen}, title = {Direct To Digital Holography For High Aspect Ratio Inspection of Semiconductor Wafers}, booktitle = {Characterization and Metrology for ULSI Technology: 2003 International Conference on Characterization and Metrology for ULSI Technology}, year = {2003}, editor = {David G. Seiler and Alain C. Diebold and Thomas J. Shaffner and Robert McDonald and Stefan Zollner and Rajinder P. Khosla and Erik M. Secula}, volume = {683}, number = {1}, pages = {254-270}, publisher = {AIP}, doi = {10.1063/1.1622480}, keywords = {ULSI; semiconductor thin films; holography; crystal defects; inspection}, location = {Austin, Texas (USA)}, url = {http://link.aip.org/link/?APC/683/254/1} } @ARTICLE{callen_most_2005, author = {J. D. Callen}, title = {Most Electron Heat Transport Is Not Anomalous; It Is a Paleoclassical Process in Toroidal Plasmas}, journal = {Physical Review Letters}, year = {2005}, volume = {94}, pages = {055002}, number = {5}, month = feb, note = {Copyright {(C)} 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {It is hypothesized that radial electron heat transport in magnetically confined toroidal plasmas results from paleoclassical Coulomb collision processes (parallel electron heat conduction and magnetic field diffusion). In such plasmas the electron temperature is equilibrated along magnetic field lines a long length L (≫ poloidal periodicity length {πR0q),} which is the minimum of the electron collision length and an effective field line length. Thus, diffusing field lines induce a radial electron heat diffusivity {M≡L/(πR0q)∼10≫1} times the magnetic field diffusivity η/μ0≃νe(c/ωp)2.}, doi = {10.1103/PhysRevLett.94.055002}, url = {http://link.aps.org/abstract/PRL/v94/e055002} } @ARTICLE{callen_experimental_1977, author = {J. D. Callen and G. L. Jahns}, title = {Experimental Measurement of Electron Heat Diffusivity in a Tokamak}, journal = {Physical Review Letters}, year = {1977}, volume = {38}, pages = {491}, number = {9}, month = feb, note = {Copyright {(C)} 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {Electron temperature perturbations produced by internal disruptions in the center of the Oak Ridge Tokamak {(ORMAK)} are followed with a multichord soft-x-ray detector array. The space-time evolution is found to be diffusive in character, but the conduction coefficient determined from a heat-pulse-propagation model is larger by a factor of 2.5-15 than that implied by the measured gross energy-containment time.}, doi = {{10.1103/PhysRevLett.38.491}}, url = {http://link.aps.org/abstract/PRL/v38/p491} } @ARTICLE{camacho_temporally_schlieren_2002, author = {Camacho, J.F. and Bliss, D.E. and Cameron, S.M.}, title = {Temporally resolved schlieren images of a laser-generated plasma }, journal = {Plasma Science, IEEE Transactions on}, year = {2002}, volume = {30}, pages = {42-43}, number = {1}, month = {Feb}, doi = {10.1109/TPS.2002.1003914}, issn = {0093-3813}, keywords = {plasma density, plasma diagnostics, plasma production by laser, schlieren systems110 ns, 15 mm, 266 nm, 5 mJ, 50 eV, 7.5 mm, Al, axial evolution, charge coupled device camera, electron density diagnostics, electron density profile, laser pulse, laser-generated plasma, long-scale length aluminum plasma, plasma expansion velocity, plasma formation, probe beam, radial evolution, schlieren diagnostic technique, schlieren images, schlieren imaging probe beam, shot-to-shot basis, temporally resolved schlieren images, time dependence, uniform illumination}, owner = {erikg}, timestamp = {2009.09.30} } @ARTICLE{candy_beta_2005, author = {J. Candy}, title = {Beta scaling of transport in microturbulence simulations}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {072307--8}, number = {7}, month = jul, doi = {10.1063/1.1954123}, keywords = {plasma fluctuations,plasma nonlinear processes,plasma pressure,plasma simulation,plasma temperature,plasma transport processes,plasma turbulence}, url = {http://link.aip.org/link/?PHP/12/072307/1} } @ARTICLE{candy_anomalous_2003, author = {J. Candy and R. E. Waltz}, title = {Anomalous Transport Scaling in the DIII-D Tokamak Matched by Supercomputer Simulation}, journal = {Physical Review Letters}, year = {2003}, volume = {91}, pages = {045001}, month = jul, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {Gyrokinetic simulation of tokamak transport has evolved sufficiently to allow direct comparison of numerical results with experimental data. It is to be emphasized that only with the simultaneous inclusion of many distinct and complex effects can this comparison realistically be made. Until now, numerical studies of tokamak microturbulence have been restricted to either (a) flux tubes or (b) electrostatic fluctuations. Using a newly developed global electromagnetic solver, we have been able to recover via direct simulation the Bohm-like scaling observed in DIII-D L-mode discharges. We also match, well within experimental uncertainty, the measured energy diffusivities.}, doi = {10.1103/PhysRevLett.91.045001}, url = {http://link.aps.org/abstract/PRL/v91/e045001} } @ARTICLE{candy_smoothness_2004, author = {J. Candy and R. E. Waltz and M. N. Rosenbluth}, title = {Smoothness of turbulent transport across a minimum-q surface}, journal = {Physics of Plasmas}, year = {2004}, volume = {11}, pages = {1879--1890}, number = {5}, month = may, doi = {10.1063/1.1689967}, keywords = {plasma toroidal confinement,plasma transport processes,plasma {turbulence,Tokamak} devices}, url = {http://link.aip.org/link/?PHP/11/1879/1} } @ARTICLE{candy_eulerian_2003, author = {J. Candy and {R.E.} Waltz}, title = {An Eulerian gyrokinetic-Maxwell solver}, journal = {Journal of Computational Physics}, year = {2003}, volume = {186}, pages = {545--581}, number = {2}, month = apr, abstract = {In this report we present a time-explicit, Eulerian numerical scheme for the solution of the nonlinear {gyrokinetic-Maxwell} equations. The treatment of electrons is fully drift-kinetic, transverse electromagnetic fluctuations are included, and profile variation is allowed over an arbitrary radial annulus. The code, gyro, is benchmarked against analytic theory, linear eigenmode codes, and nonlinear electrostatic gyrokinetic particle-in-cell codes. We have attempted preliminary finite-[beta] calculations in the range [beta]/[beta]crit=[0.0,0.5] for a reference discharge. Detailed diagnostic data is presented for these simulations, along with a number of caveats which reflect the uncharted nature of the parameter regime.}, doi = {{10.1016/S0021-9991(03)00079-2}}, issn = {0021-9991}, keywords = {{Eulerian,Gyrokinetic,Turbulence}}, url = {http://www.sciencedirect.com/science/article/B6WHY-4840PJN-9/2/86091b696f04a5e937b1c1ec3ec774aa} } @ARTICLE{cardozo_perturbative_1995, author = {N. J. Lopes Cardozo}, title = {Perturbative transport studies in fusion plasmas}, journal = {Plasma Physics and Controlled Fusion}, year = {1995}, volume = {37}, pages = {799--852}, number = {8}, abstract = {Studies of transport in fusion plasmas using perturbations of an equilibrium state are reviewed. Essential differences between steady-state and perturbative transport studies are pointed out. Important transport issues that can be addressed with perturbative experiments are identified as: (i) Are the transport relations linear (or nearly so)? (ii) What are the dominant dependences on plasma parameters; can they be understood from theory? (iii) Are there significant off-diagonal terms in the transport matrix? If so, how important are these for global confinement? (iv) Do the data obtained with perturbative experiments indicate that tokamak performance can be optimized along lines different from those presently explored? The theoretical framework for perturbative transport experiments is given. It is shown that perturbative experiments yield transport coefficients that are essentially different from the steady-state transport coefficients. In particular, when transport can be described by a transport matrix with off-diagonal elements, a perturbative experiment yields (one or more of) the eigenvalues of the matrix. In contrast, the coefficients obtained by steady-state analysis are linear combinations of the matrix coefficients, with the actual values of the various gradients as multipliers. Hence, the outcome of a steady-state transport evaluation depends on the actual values of the gradients, whereas a perturbative experiment measures the underlying transport matrix. Experimental perturbation techniques and techniques for data analysis are reviewed. Perturbations include the sawtooth instability, oscillatory gas feed, modulated power input, pellet injection etc. Data analysis techniques range from the time-to-peak analysis employed in sawtooth pulse propagation through Fourier or Laplace transforms, to direct numerical modelling. A review of the most important sources of systematic error is given.}, issn = {0741-3335}, keywords = {heat pulse propagation,review,transport}, url = {http://www.iop.org/EJ/abstract/0741-3335/37/8/001} } @ARTICLE{catto_isothermal_2006, author = {Peter J. Catto and R. D. Hazeltine}, title = {Isothermal tokamak}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {122508--10}, number = {12}, month = dec, doi = {10.1063/1.2403090}, keywords = {plasma density,plasma flow,plasma kinetic theory,plasma toroidal confinement,plasma transport processes,plasma-wall {interactions,Tokamak} devices}, url = {http://link.aip.org/link/?PHP/13/122508/1} } @ARTICLE{catto_two-dimensional_1994, author = {Peter J. Catto and R. D. Hazeltine}, title = {A two-dimensional kinetic model of the scrape-off layer}, journal = {Physics of Plasmas}, year = {1994}, volume = {1}, pages = {1882-1889}, month = jun, keywords = {BOUNDARY CONDITIONS,DIVERTORS,HOT PLASMA,ION DENSITY,ION TEMPERATURE,KINETIC EQUATIONS,LIMITERS,PLASMA SHEATH,PLASMA-WALL INTERACTIONS,TOKAMAK DEVICES,WALL EFFECTS, SOL, 2yr\_project}, url = {http://link.aip.org/link/?PHP/1/1882/1} } @ARTICLE{catto_linearized_1977, author = {P. J. Catto and K. T. Tsang}, title = {Linearized gyro-kinetic equation with collisions}, journal = {Physics of Fluids}, year = {1977}, volume = {20}, pages = {396--401}, number = {3}, month = mar, doi = {10.1063/1.861902}, url = {http://link.aip.org/link/?PFL/20/396/1} } @ARTICLE{1971AuJPh..24..859C, author = {Cawthron, E.~R.}, title = {Secondary electron emission from solid surfaces bombarded by medium energy ions}, journal = {Australian Journal of Physics}, year = {1971}, volume = {24}, pages = {859-+}, month = dec, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1971AuJPh..24..859C}, url = {http://adsabs.harvard.edu/abs/1971AuJPh..24..859C} } @ARTICLE{chacon_implicit_2000, author = {L. Chac\'on and D. C. Barnes and D. A. Knoll and G. H. Miley}, title = {An Implicit {Energy-Conservative} {2D} {Fokker-Planck} Algorithm: I. Difference Scheme}, journal = {Journal of Computational Physics}, year = {2000}, volume = {157}, pages = {618--653}, number = {2}, abstract = {Numerical energy conservation in {Fokker-Planck} problems requires the energy moment of the {Fokker-Planck} equation to cancel exactly. However, standard discretization techniques not only do not observe this requirement (thus precluding exact energy conservation), but they also demand very refined meshes to keep the energy error under control. In this paper, a new difference scheme for multidimensional {Fokker-Planck} problems that improves the numerical cancellation of the energy moment is proposed. Crucial to this new development is the reformulation of the friction term in the {Fokker-Planck} collision operator using Maxwell stress tensor formalism. As a result, the {Fokker-Planck} collision operator takes the form of a double divergence operating on a tensor, which is suitable for particle and energy conservative differencing. Numerical results show that the new discretization scheme improves the cancellation of the energy moment integral over standard approaches by at least an order of magnitude.}, doi = {10.1006/jcph.1999.6394}, issn = {0021-9991}, url = {http://www.sciencedirect.com/science/article/B6WHY-45FC8S7-81/2/2c878e2c3b544bdb05d2a47fea9405be} } @ARTICLE{chacon_implicit_2000-1, author = {L. Chac\'on and D. C. Barnes and D. A. Knoll and G. H. Miley}, title = {An Implicit {Energy-Conservative} {2D} {Fokker-Planck} Algorithm: {II.} {Jacobian-Free} {Newton-Krylov} Solver}, journal = {Journal of Computational Physics}, year = {2000}, volume = {157}, pages = {654--682}, number = {2}, abstract = {Energy-conservative implicit integration schemes for the {Fokker-Planck} transport equation in multidimensional geometries require inverting a dense, non-symmetric matrix {(Jacobian),} which is very expensive to store and solve using standard solvers. However, these limitations can be overcome with {Newton-Krylov} iterative techniques, since they can be implemented Jacobian-free (the Jacobian matrix from Newton's algorithm is never formed nor stored to proceed with the iteration), and their convergence can be accelerated by preconditioning the original problem. In this document, the efficient numerical implementation of an implicit energy-conservative scheme for multidimensional {Fokker-Planck} problems using multigrid-preconditioned Krylov methods is discussed. Results show that multigrid preconditioning is very effective in speeding convergence and decreasing {CPU} requirements, particularly in fine meshes. The solver is demonstrated on grids up to 128×128 points in a {2D} cylindrical velocity space (vr, vp) with implicit time steps of the order of the collisional time scale of the problem, [tau]. The method preserves particles exactly, and energy conservation is improved over alternative approaches, particularly in coarse meshes. Typical errors in the total energy over a time period of 10[tau] remain below a percent.}, doi = {10.1006/jcph.1999.6395}, issn = {0021-9991}, url = {http://www.sciencedirect.com/science/article/B6WHY-45FC8S7-82/2/ce78bccfbb5a594b4ab532a9873aa8a2} } @ARTICLE{charles_current-free_2003, author = {Christine Charles and Rod Boswell}, title = {Current-free double-layer formation in a high-density helicon discharge}, journal = {Applied Physics Letters}, year = {2003}, volume = {82}, pages = {1356--1358}, number = {9}, month = mar, doi = {10.1063/1.1557319}, keywords = {argon, high-frequency discharges, plasma boundary layers, plasma flow, plasma sources, plasma temperature, plasma transport processes}, url = {http://link.aip.org/link/?APL/82/1356/1} } @ARTICLE{charlesboswell2004, author = {C.~Charles and R.~W.~Boswell}, title = {Time development of a current-free double-layer}, journal = {Physics of Plasmas}, year = {2004}, volume = {11}, pages = {3808}, number = {8}, month = aug, note = {In the discussion section, the authors give some physical insight into what is going on: During breakdown, electrons leave the plasma, and it develops a high $V_p$; ions are accelerated out, until electron and ion currents to the walls are equal. If the walls were conducting, then the system would settle to state where $V_f$ were zero, but since the walls are floating and the plasma is expanding, Boltzman relation for electrons requires a potential difference to be set up to balance the pressure gradient, assuming constant $T_e$. In this case, the density drops a factor of 100, and $T_e \sim 5$eV, so the potential drop in the plasma must be at least 25 V. At the top and bottom of the source, the plasma potential must be about 5x higher than the wall potential (for Argon) giving 25V between the wall and plasma potential. If the wall at the end of the source is at ground and is electrically connected to the wall at the end of the expansion region, the Boltzman relation demands that the 25V drop be carried in the plasma, inconsistent with its low resistivity. This drop could come from currents in the walls if they were conducting, but since they are insulating, the source walls must acquire a charge to allow the potential drop to occur in the plasma. High value of the floating potential in the source $\sim 15$ eV seems a key indicator for the DL formation.}, doi = {10.1063/1.1764829}, keywords = {double layer, 1yr_project}, owner = {egranste}, timestamp = {2007.06.28} } @ARTICLE{charlesboswelthruster2006, author = {C.~Charles and R.~W.~Boswell and M.~A.~Lieberman}, title = {Xenon ion beam characterization in a helicon double layer thruster}, journal = {Applied Physics Letters}, year = {2006}, volume = {89}, pages = {261503}, number = {26}, month = dec, note = {The Helicon Double Layer Thruster (HDLT) using 500W rf power, 0.07mTorr gas pressure, max B field of 125 G, measured a beam velocity of 6 km/s, 150 $\textrm{cm^2}$ beam area, and less than 6 degrees beam divergence. From previous paper, DL strength is few times $T_e$; with Xe ions, $V_{DL} \sim 18.5V$, since the source chamber had a voltage of 31V and $V_{beam} \sim 49.5 V$. Double peak in IEDF seen, with a population of low-energy ions at the chamber voltage and beam ions at the higher voltage. Cutoff dor DL formation exists at a lower pressure for Xenon than for Argon, validating the Lieberman theory. DL potential drop (and hence resulting beam) appears to be radially uniform. 4 grid RPA was used for IEDF measurements. $N_{beam}$ appears to peak at $r = 4$ cm, and since the beam velocity is constant for $r= 0--8$ cm, this results from the radial density profile upstream of the DL (the helicon coupling mechanism); this ``double-hump'' density profile is a common feature of a high-density coupling mode. Low divergence indicates the beam profile is determined primarily by the DL and not by the diverging B field.}, keywords = {double layers, thruster, 1yr_project}, owner = {egranste}, timestamp = {2007.07.05} } @ARTICLE{chen_simulations_2003, author = {Y. Chen and S.E. Parker and B.I. Cohen and A.M. Dimits and W.M. Nevins and D. Shumaker and V.K. Decyk and J.N. Leboeuf}, title = {Simulations of turbulent transport with kinetic electrons and electromagnetic effects}, journal = {Nuclear Fusion}, year = {2003}, volume = {43}, pages = {1121-1127}, abstract = {A new electromagnetic kinetic electron simulation model that uses a generalized split-weight scheme, where the adiabatic part is adjustable, along with a parallel canonical momentum formulation has been developed in three-dimensional toroidal flux-tube geometry. This model includes electron-ion collisional effects and has been linearly benchmarked. It is found that for H-mode parameters, the nonadiabatic effects of kinetic electrons increase linear growth rates of the ion-temperature-gradient-driven (ITG) modes, mainly due to trapped-electron drive. The ion heat transport is also increased from that obtained with adiabatic electrons. The linear behaviour of the zonal flow is not significantly affected by kinetic electrons. The ion heat transport decreases to below the adiabatic electron level when finite plasma b is included due to finite-b stabilization of the ITG modes. This work is being carried out using the 'Summit Framework'.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/43/10/013} } @ARTICLE{chen_[delta]f_2003, author = {Yang Chen and Scott E. Parker}, title = {A [delta]f particle method for gyrokinetic simulations with kinetic electrons and electromagnetic perturbations}, journal = {Journal of Computational Physics}, year = {2003}, volume = {189}, pages = {463-475}, month = aug, abstract = {A [delta]f particle simulation method is developed for solving the gyrokinetic-Maxwell system of equations that describes turbulence and anomalous transport in toroidally confined plasmas. A generalized split-weight scheme is used to overcome the constraint on the time step due to fast parallel motion of the electrons. The inaccuracy problem at high plasma [beta] is solved by using the same marker particle distribution as is used for [delta]f to evaluate the [beta]mi/meA[short parallel] term in Ampere's equation, which is solved iteratively. The algorithm is implemented in three-dimensional toroidal geometry using field-line-following coordinates. Also discussed is the implementation of electron-ion collisional effects which are important when kinetic electron physics is included. Linear benchmarks in toroidal geometry are presented for moderate [beta], that is, [beta]<<1, but [beta]mi/me>>1. Nonlinear simulation results with moderate [beta] are also presented.}, doi = {10.1016/S0021-9991(03)00228-6}, keywords = {[delta]f method,Electromagnetic,Gyrokinetic simulation,Split-weight scheme}, url = {http://www.sciencedirect.com/science/article/B6WHY-48JCC75-1/2/86c24de488c90bec59d7de1ef85a02f0} } @INCOLLECTION{chirikov1984particle, author = {Chirikov, B.~V.}, title = {Particle Dynamics in Magnetic Traps}, booktitle = {Reviews of Plasma Physics}, publisher = {Consultants Bureau}, year = {1984}, editor = {Kadomtsev, B.~B}, pages = {1--91}, address = {New York}, keywords = {mirrors, open systems, 2yr_project}, owner = {erikg}, timestamp = {2007.12.06} } @ARTICLE{cho_particle_1990, author = {M-H. Cho and N. Hershkowitz and T. Intrator}, title = {Particle and power balances of hot-filament discharge plasmas in a multidipole device}, journal = {Journal of Applied Physics}, year = {1990}, volume = {67}, pages = {3254-3259}, month = apr, url = {http://link.aip.org/link/?JAP/67/3254/1} } @ARTICLE{cho_temporal_1988, author = {M. H. Cho and N. Hershkowitz and T. Intrator}, title = {Temporal evolution of collisionless sheaths}, journal = {Journal of Vacuum Science \& Technology A: Vacuum, Surfaces, and Films}, year = {1988}, volume = {6}, pages = {2978-2986}, url = {http://link.aip.org/link/?JVA/6/2978/1} } @ARTICLE{2001PhPl....8.1411C, author = {{Choueiri}, E.~Y.}, title = {Plasma oscillations in Hall thrusters}, journal = {Physics of Plasmas}, year = {2001}, volume = {8}, pages = {1411-1426}, month = apr, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2001PhPl....8.1411C}, doi = {10.1063/1.1354644}, keywords = {Hall thruster, 1yr_project} } @ARTICLE{coda_decorrelation_2000, author = {S. Coda and M. Porkolab and K. H. Burrell}, title = {Decorrelation of edge plasma turbulence at the transition from low- to high-confinement mode in the DIII-D Tokamak}, journal = {Physics Letters A}, year = {2000}, volume = {273}, pages = {125-131}, month = aug, abstract = {The modification of turbulence in the edge plasma of the DIII-D tokamak at the transition from the low to the high mode of confinement is investigated with a phase-contrast imaging diagnostic. The amplitude and radial correlation length of the turbulence in the confinement region decrease at the transition, whereas the decorrelation time increases. The transition model of Biglari, Diamond, and Terry [Phys. Fluids B 2 (1990) 1], based on turbulence decorrelation by E?B velocity shear, is quantitatively substantiated by measurements of the theoretical control parameter. Further quantitative predictions of the theory are tested for the first time.}, doi = {10.1016/S0375-9601(00)00460-6}, keywords = {L-H transition,Plasma transport,Plasma turbulence,Sheared flow,Tokamaks}, url = {http://www.sciencedirect.com/science/article/B6TVM-4106G0P-K/2/30ff905b56d938bd1dc1713ff94f7793} } @ARTICLE{coda_phase_1992, author = {S. Coda and M. Porkolab and T. N. Carlstrom}, title = {A phase contrast interferometer on DIII-D}, journal = {Proceedings of the 9th topical conference on high temperature plasma diagnostics}, year = {1992}, volume = {63}, pages = {4974-4976}, month = oct, doi = {10.1063/1.1143516}, keywords = {FLUCTUATIONS,IMAGES,INTERFEROMETRY,PHASE CONTRAST MICROSCOPY,PHASE MODULATION,PHASE SHIFT,PLASMA DIAGNOSTICS,PLASMA WAVES,SPATIAL RESOLUTION,TOKAMAK DEVICES}, url = {http://link.aip.org/link/?RSI/63/4974/1} } @ARTICLE{cohen_sheath_2004, author = {R. H. Cohen and D. D. Ryutov}, title = {Sheath Physics and Boundary Conditions for Edge Plasmas}, journal = {Contributions to Plasma Physics}, year = {2004}, volume = {44}, pages = {111-125}, note = {Article also reviews other works well.}, abstract = {The boundary conditions of mass, momentum, energy, and charge appropriate for fluid formulations of edge plasmas are surveyed. We re-visit the classic problem of 1-dimensional flow, and note that the ldquoBohm sheath criterionrdquo is requirement of connectivity of the interior plasma with the external world, not the result of termination of the plasma by a wall. We show that the nature of the interior plasma solution is intrinsically different for ion sources that inject above and below the electron sound speed. We survey the appropriate conditions to apply, and resultant fluxes, for a magnetic field obliquely incident on a wall, including the presence of drifts and radial transport. We discuss the consequences of toroidal asymmetries in wall properties, as well as experimental tests of such effects. Finally, we discuss boundary-condition modifications in the case of rapidly varying plasma conditions. (? 2004 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim)}, doi = {10.1002/ctpp.200410016}, keywords = {plasma expansion,scrape-off layer,sheath}, url = {http://dx.doi.org/10.1002/ctpp.200410016} } @ARTICLE{cohen_progress_2008, author = {R. H. Cohen and X. Q. Xu}, title = {Progress in Kinetic Simulation of Edge Plasmas}, journal = {Contributions to Plasma Physics}, year = {2008}, volume = {48}, pages = {212--223}, number = {1-3}, abstract = {Kinetic codes are required for quantitative simulation of edge plasmas of most tokamaks, because orbit widths can be comparable to radial scale lengths and because mean free paths can be comparable to scale lengths along the magnetic field. However, the edge presents special challenges for edge simulation, both in terms of formulation and implementation. There are two major approaches to kinetic simulation, namely particle-based and continuum- (high-dimensional fluid-) based. The edge presents challenges common to both approaches as well as ones that are unique to each approach. In this paper we review these challenges, and survey how they are being addressed in current edge kinetic simulation projects, as well as the status and accomplishments of those projects. We discuss in some detail the status and recent accomplishments of the {U.S.} Edge Simulation Laboratory {(ESL),} a project based on the continuum approach. The {ESL} currently consists of a main-line effort to develop a code based on high-order conservative finite-volume discretization, as well as two prototype activities, {TEMPEST} and {EGK.} These prototype codes are exploring issues attached to energy-magnetic moment and parallel velocity-magnetic moment representations, respectively, as well as physics issues associated with simulation in a steep radial gradient region and a domain that includes both open field lines and closed flux surfaces. (� 2008 {WILEY-VCH} Verlag {GmbH} \& Co. {KGaA,} Weinheim)}, doi = {10.1002/ctpp.200810038}, url = {http://dx.doi.org/10.1002/ctpp.200810038} } @ARTICLE{cohen_2006_FRC, author = {S.A. Cohen}, title = {Formation of collisionless high-beta plasmas by odd-parity rotating magnetic fields}, journal = {unpublished}, year = {2006}, volume = {n/a}, pages = {n/a}, month = nov, file = {Docs\\FRC\\Cohen_2006_FRC.pdf:Docs\\FRC\\Cohen_2006_FRC.pdf:PDF}, keywords = {FRC}, owner = {egranste}, timestamp = {2007.03.07} } @ARTICLE{cohen03, author = {S.A. Cohen and N.S. Siefert and S. Stange and R.F. Boivin and E.E. Scime and F.M. Levinton}, title = {Ion acceleration in plasmas emerging from a helicon-heated magnetic-mirror device}, journal = POP, year = {2003}, volume = {10}, pages = {2593}, number = {6}, month = jun, note = {Magnetic-mirror device shown to accelerate argon ions up to $\sim$30 eV, above the ion-acoustic speed and ion-thermal speed. On page 2, why are double layers uncommon in the parameter range $\omega_{pe}/\omega_{ce} \geq 1$? I think because in this range, the electric field is not strong enough to affect electron mobility; on the other hand, the B field doesn't affect axial motion, so I don't understand why that would affect the formation of an axial DL. The LIF signal shows low-energy ions (LEP) with $T_i \sim 0.2$ eV and also a high-energy population (HEP) at 17 eV axial energy. The HEP was never observed in the main chamber, leading the author to conclude that the HEP is due to ions accelerated during their passage through the nozzle. the LEP grows linearly with the pressure in the expansion region ($p_{er}$), consistent with the understanding that the low energy meta-stable Argon ions are created by ionization of the neutrals in the ER. On the other hand, the HEP decreases exponentially with pressure. Taking into account ion-neutral collisions can mostly account for the decrease in the HEP with distance, radial transport and electron impact could account for the discreptancy. $p_{er}$ increases when the nozzle-coil current is increased, and contrary to what one would expect, increased magnetic-mirror ratio at the nozzle coil doesn't seem to reduce the flux through the nozzle, because the orfice is small compared to the plasma chamber diameter, and because ions in the main chamber are collisional. The amplitude of the HEP increases approximately proportional to the magnetic flux, but HEP energy doesn't seem to be effected. On page 2597, the authors suggest a DL exists just beyond the nozzle, with thermal rather than beam electrons as the most likely source for the electric field. An axial field is thought to exist, because ion temperature in the main chamber is low, an increased nozzle field does not increase the ion energy, and ions continue to be accelerated outside the nozzle to 4x $T_E$ in the main discharge. The HEP amplitude decreases farther into the expansion region (due to field expansion), but the LEP does not decrease, but rather grows slightly. The energy of the HEP also increases with distance. In the Laval-nozzle picture, ions reach their sound speed at the throat, and a maximum energy at infinite expansion of $\gamma T_e/(\gamma -1)=17.5$ eV at infinite expansion, but the maximum measured energy is higher (30 eV). This is in agreement with the ambipolar-flow, thermal conduction model of ref 11. As I understand it, ambipolar potential increases the ion velocity while decreasing the electron velocity. The experiment does not show the expected decrease in the electron temperature, however.}, file = {\\Docs\\Double Layers\\cohen03.pdf:\\Docs\\Double Layers\\cohen03.pdf:PDF}, keywords = {helicon, double layers, 1yr_project} } @ARTICLE{cohen_theory_2007, author = { {RH} Cohen and B {LaBombard} and {DD} Ryutov and {JL} Terry and {MV} Umansky and {XQ} Xu and S Zweben}, title = {Theory and fluid simulations of boundary-plasma fluctuations}, journal = {{NUCLEAR} {FUSION}}, year = {2007}, volume = {47}, pages = {612--625}, number = {7}, month = jul, abstract = {Theoretical and computational investigations of boundary-plasma microturbulence which take into account important effects of the geometry of diverted tokamaks-in particular, the effect of X-point magnetic shear and the termination of field lines on divertor plates-are presented. We first generalize our previous 'heuristic boundary condition' which describes, in a lumped model, the closure of currents in the vicinity of the X-point region to encompass three current-closure mechanisms. We then use this boundary condition to derive the dispersion relation for low-beta flute-like modes in the divertor-leg region under the combined drives of curvature, sheath impedance and divertor tilt effects. The results indicate the possibility of strongly growing instabilities, driven by sheath boundary conditions, and localized in either the private or common flux region of the divertor leg depending on the radial tilt of divertor plates. We revisit the issue of X-point effects on blobs, examining the transition from blobs terminated by X-point shear to blobs that extend over both the main {SOL} and divertor legs. We find that, for a {main-SOL} blob, this transition occurs without a free-acceleration period as previously thought, with X-point termination conditions applying until the blob has expanded to reach the divertor plate. We also derive propagation speeds for divertor-leg blobs. Finally, we present fluid simulations of the {C-Mod} tokamak from the {BOUT} edge fluid turbulence code, which show {main-SOL} blob structures with similar spatial characteristics to those observed in the experiment, and also simulations which illustrate the possibility of fluctuations confined to divertor legs.}, doi = {10.1088/0029-5515/47/7/012}, issn = {0029-5515}, url = {http://apps.isiknowledge.com/full_record.do?product=WOS&search_mode=AuthorFinder&qid=2&SID=1Dl9P6J367@AakpdBLC&page=1&doc=8&cacheurlFromRightClick=no} } @ARTICLE{cohen_dynamics_2006, author = { {RH} Cohen and {DD} Ryutov}, title = {Dynamics of an isolated blob in the presence of the X-point}, journal = {{CONTRIBUTIONS} {TO} {PLASMA} {PHYSICS}}, year = {2006}, volume = {46}, pages = {678--684}, number = {7-9}, abstract = {The interplay of X-point shearing and axial plasma redistribution along a moving flux tube is discussed. Blobs limited to the main scrape-off-layer and blobs entirely confined in the divertor region are identified. A strong effect of the radial tilt of the divertor plate on "divertor" blobs is found. (c) 2006 {WILEY-VCH} Verlag {GmbH} \& Co. {KGaA,} Weinheim.}, doi = {10.1002/ctpp.200610063}, issn = {0863-1042}, url = {http://apps.isiknowledge.com/full_record.do?product=WOS&search_mode=AuthorFinder&qid=2&SID=1Dl9P6J367@AakpdBLC&page=2&doc=18&cacheurlFromRightClick=no} } @BOOK{eps_conference_on_controlled_fusion_and_plasma_physics_26th_1999, title = {26th European Physical Society Conference on Controlled Fusion and Plasma Physics: Maastricht, 14-18 June 1999: Contributed Papers}, publisher = {European Physical Society}, year = {1999}, author = {EPS Conference on Controlled Fusion and Plasma Physics and B. Schweer and G. van Oost and E. Vietzke}, pages = {1}, series = {Europhysics conference abstracts}, address = {Geneva}, keywords = {Controlled fusion,Plasma confinement,Plasma heating,Plasma (Ionized gases)} } @ARTICLE{conway_microwave_2006, author = {G.D. Conway}, title = {Microwave reflectometry for fusion plasma diagnosis}, journal = {Nuclear Fusion}, year = {2006}, volume = {46}, pages = {S665-S669}, issn = {0029-5515}, url = {http://www.iop.org/EJ/toc/0029-5515/46/9} } @ARTICLE{coppi67, author = {Coppi and Rosenbluth and Sagdeev}, journal = {Physics of Fluids}, year = {1967}, volume = {10}, pages = {582}, keywords = {GPP2, ITG mode, Ion Temperature Gradient, drift waves}, owner = {erikg}, timestamp = {2007.05.09} } @ARTICLE{coppi_candidate_1990, author = {B. Coppi and S. Migliuolo and {Y-K.} Pu}, title = {Candidate mode for electron thermal energy transport in {multi-keV} plasmas}, journal = {Physics of Fluids B: Plasma Physics}, year = {1990}, volume = {2}, pages = {2322--2333}, number = {10}, month = oct, doi = {10.1063/1.859497}, keywords = {trapped-particle instability, TEM, CTEM, fluid TEM, drift waves, trapped electron mode, landau damping}, url = {http://link.aip.org/link/?PFB/2/2322/1} } @ARTICLE{coppi_fluid-like_1974, author = {B. Coppi and G. Rewoldt}, title = {Fluid-like instability of trapped electrons in confined plasmas}, journal = {Physics Letters A}, year = {1974}, volume = {49}, pages = {36--38}, number = {1}, month = aug, abstract = {An instability, which does not depend on mode-particle resonances, can be driven by the drift of trapped electrons in the unfavorable curvature region of the confining magnetic field for selected values of the relevant mode transverse wavelengths.}, doi = {10.1016/0375-9601(74)90658-6}, issn = {0375-9601}, url = {http://www.sciencedirect.com/science/article/B6TVM-46X9P96-C9/2/13698247fdbd8045149f9ec76a2d1bc6} } @ARTICLE{coppi_new_1974, author = {Bruno Coppi and Gregory Rewoldt}, title = {New {Trapped-Electron} Instability}, journal = {Physical Review Letters}, year = {1974}, volume = {33}, pages = {1329}, number = {22}, month = nov, note = {Copyright (C) 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {We have found a new instability that is driven by a radial gradient of the electron temperature or by the electron drift in the "unfavorable" curvature of the magnetic field lines for high-temperature confined plasmas in which a fraction of the electron population is magnetically trapped. The relevant mode is standing along the magnetic field, is symmetric about the point of minimum field, and has relatively short wavelengths across the magnetic field.}, doi = {{10.1103/PhysRevLett.33.1329}}, url = {http://link.aps.org/abstract/PRL/v33/p1329} } @ARTICLE{coppi_theory_1977, author = { B {COPPI} and F {PEGORARO}}, title = {{THEORY} {OF} {UBIQUITOUS} {MODE}}, journal = {{NUCLEAR} {FUSION}}, year = {1977}, volume = {17}, pages = {969--993}, number = {5}, issn = {0029-5515}, url = {http://apps.isiknowledge.com/full_record.do?product=WOS&search_mode=AuthorFinder&qid=1&SID=2EOf8BNcJmB6IMDF3hF&page=14&doc=137} } @ARTICLE{cornelis_predicting_1994, author = {J. Cornelis and R. Sporken and G. van Oost and R.R. Weynants}, title = {Predicting the radial electric field imposed by externally driven radial currents in tokamaks}, journal = {Nuclear Fusion}, year = {1994}, volume = {34}, pages = {171-183}, abstract = {H mode behaviour is usually linked to the existence of radial electric fields or to their shear at the edge of tokamaks. The mechanisms are investigated by which such fields are induced in the plasma edge and by which the profile shaping is obtained when radial currents are imposed by electrode polarization. Earlier detailed experimental field measurements are successfully compared with a theoretical conductivity model in which neoclassical non-ambipolar transport and mobility through ion-neutral collisions are predominant. Strong neoclassical viscosity in the bulk plasma allows significant fields to develop only at the very edge of the plasma. There, a delicate balance between viscosity and ion-neutral friction takes place, which strongly affects the magnitude of the fields and the spatial location and the threshold condition for L-H field bifurcation. It is also shown how to verify experimentally the neoclassical diffusion coefficients in the plateau regime}, doi = {10.1088/0029-5515/34/2/I01}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/34/2/I01} } @INPROCEEDINGS{courtney_diverging_2007, author = {Daniel Courtney and Mart\'inez-S\'anchez}, title = {Diverging Cusped-field Hall Thruster (DCHT)}, booktitle = {30th International Electric Propulsion Conference}, year = {2007}, series = {IEPC paper 2007-39}, address = {Florence, Italy}, month = {SEP}, keywords = {1yr_project, Hall Thruster}, owner = {erikg}, timestamp = {2008.03.03}, url = {http://www.me.mtu.edu/researchAreas/isp/publications.html} } @INPROCEEDINGS{crocker_global_mode_structure_2006, author = {N.A.~Crocker and S.~Kubota and W.A.~Peebles and G.~Wang and X.V.~Nguyen and G.J.~Kramer}, title = {Measurement of global mode structure using millimeter-wave reflectometry and interferometry}, booktitle = {16th Topical Conference on High Temperature Plasma Diagnostics}, year = {2006}, address = {Williamsburg, VA}, month = {MAY}, publisher = {unpublished}, keywords = {reflectometry, inteferometry, interferometer, fast particle, fast particles, alfven eigenmodes}, owner = {erikg}, timestamp = {2009.04.01} } @ARTICLE{1402-4896-1982-T2B-024, author = {D Gr\'{e}sillon, C Stern, A H\'{e}mon, A Truc, T Lehner, J Olivain, A Qu\'{e}meneur, F Gervais and Y Lapierre}, title = {Density Fluctuation Measurement by Far Infrared Light Scattering}, journal = {Physica Scripta}, year = {1982}, volume = {T2B}, pages = {459-466}, abstract = {Density fluctuation observation can be obtained by scattering of electromagnetic radiation. New developments and applications are presented. By heterodyne detection the scattered signal is shown to be the time variation of a space Fourier transform of the density. The antenna beam, that especially defines the sensitivity, is experimentally investigated. The time variation is used in two occurrences, to check quantum efficiency uniformity on detectors area, and in an air turbulence where the interspectrum is obtained between two scattering devices looking at different regions. Calibration formulas are given for quantitative measurement of density fluctuation spectrum. Observations are also reported on a tokamak plasma, on the drift wave spectrum, and on a new second order group of oscillations that were observed during ion cyclotron radio-frequency heating. The analysis shows this new group is a forced oscillation by beating of the drift waves with the high-frequency heating wave, and its amplitude provides a measurement of the HF wave electric field.}, keywords = {diagnostics, fluctuations}, url = {http://stacks.iop.org/1402-4896/T2B/459} } @BOOK{dhaeseleer_flux_1991, title = {Flux Coordinates and Magnetic Field Structure: A Guide to a Fundamental Tool of Plasma Structure}, publisher = {Springer-Verlag}, year = {1991}, author = {W. D D'haeseleer}, pages = {241}, series = {Springer series in computational physics}, address = {Berlin}, keywords = {Magnetic fields,Plasma (Ionized gases)} } @UNPUBLISHED{shortswim, author = {D.B. Batchelor, et.al.}, title = {Scientific Discovery through Advanced Computing Proposal: Center for Simulation of Wave-Plasma Interactions}, note = {Swim proposal}, month = mar, year = {2005}, file = {\\Docs\\general papers\\shortswim.pdf:\\Docs\\general papers\\shortswim.pdf:PDF}, keywords = {computation, wave-particle, stabilization}, owner = {egranste}, timestamp = {2007.03.08} } @INPROCEEDINGS{ernst_itb_tem_iaea_2004, author = {D.R. Ernst, N. Basse, P.T. Bonoli, P.J. Catto, W. Dorland, C.L. Fiore, M. Greenwald, A.E. Hubbard, E.S. Marmar, M. Porkolab, J.E. Rice, K. Zeller, K. Zhurovich}, title = {Mechanisms for ITB Formation and Control in Alcator C-Mod Identified through Gyrokinetic Simulations of TEM Turbulence}, booktitle = {20th IAEA Fusion Energy Conference (Villamoura, Portugal)}, year = {2004}, pages = {TH/4-1}, address = {Vienna}, month = {NOV}, organization = {IAEA}, abstract = {Mechanisms for transport barrier control are elucidated via nonlinear gyrokinetic turbulence simulations of trapped electron mode (TEM) turbulence in internal particle transport barriers in Alcator C-Mod, produced with off-axis RF heating. The simulations reveal new nonlinear physics of TEM turbulence and explain the observed transport barrier (density profile) control with on-axis RF heating. The critical density gradient for onset of TEM turbulent transport is nonlinearly up-shifted. Upon exceeding this nonlinear critical gradient, the turbulent particle diffusivity from GS2 gyrokinetic simulations matches the particle diffusivity from transport analysis, within experimental error bars. A stable equilibrium is established with the TEM turbulent diffusion balancing the Ware pinch in the ITB. This equilibrium is sensitive to temperature through gyroBohm scaling of the turbulent transport, which allows control of the density profile with on-axis RF heating. With no core particle source and ~ 1 mm resolution density diagnostics, the C-Mod experiments provide a nearly ideal test bed for particle transport studies.}, keywords = {internal transport barrier, ITB, density control, trapped electron mode, TEM}, owner = {erikg}, timestamp = {2008.09.26}, url = {http://www-naweb.iaea.org/napc/physics/fec/fec2004/datasets/TH_4-1.html} } @ARTICLE{siegfriedwilbur, author = {{D.~E.~Siegfried} and {P.~J.~Wilbur}}, title = {An Investigation of Mercury Hollow Cathode Phenomena}, journal = {AIAA}, keywords = {hollow cathode, Hall thruster, 1yr_project}, owner = {erikg}, timestamp = {2007.08.20} } @ARTICLE{dannert_gyrokinetic_2005, author = {Tilman Dannert and Frank Jenko}, title = {Gyrokinetic simulation of collisionless trapped-electron mode turbulence}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {072309--8}, number = {7}, month = jul, doi = {10.1063/1.1947447}, keywords = {plasma flow, plasma fluctuations, plasma instability, plasma simulation, plasma toroidal confinement, plasma transport processes, plasma turbulence, Tokamak devices, Vlasov equation, TEM}, url = {http://link.aip.org/link/?PHP/12/072309/1} } @ARTICLE{dannert_vlasov_2004, author = {Tilman Dannert and Frank Jenko}, title = {Vlasov simulation of kinetic shear Alfven waves}, journal = {Computer Physics Communications}, year = {2004}, volume = {163}, pages = {67-78}, month = nov, abstract = {The treatment of kinetic shear Alfven waves in homogeneous magnetized plasmas by means of Vlasov simulation is examined. To this end, the driftkinetic version of the Vlasov-Maxwell equations is solved via various numerical schemes, all employing a grid in (1+1)D phase space. Since kinetic shear Alfven waves are Landau damped, the use of an equidistant grid in velocity space leads to a recurrence problem. The latter can be circumvented, however, by damping the finest velocity space scales through higher-order collision operators. Of particular interest is the question if and under which circumstances the magnetohydrodynamic limit (small perpendicular wavenumber) can be recovered.}, keywords = {Alfven waves,Vlasov simulation,recurrence_project}, url = {http://www.sciencedirect.com/science/article/B6TJ5-4DFKC0R-3/2/b554775a8310fc19ed4669372ab0804f} } @BOOK{davidson_physics_2001, title = {Physics of Nonneutral Plasmas}, publisher = {Imperial College Press}, year = {2001}, author = {Ronald C Davidson}, pages = {733}, address = {London}, isbn = {1860943020}, keywords = {Nonneutral,plasma} } @BOOK{dawson_quadrupole_1976, title = {Quadrupole mass spectrometry and its applications}, publisher = {Elsevier Scientific Pub. Co.}, year = {1976}, author = {Peter H. Dawson}, pages = {349}, address = {New York}, keywords = {pressure gauge,residual gas analyzer, 1yr_project}, url = {http://catalog.princeton.edu/cgi-bin/Pwebrecon.cgi?SAB1=dawson\&BOOL1=all+of+these\&FLD1=Author+\%28NAMP\%29\&GRP1=AND+with+next+set\&SAB2=quadrupole\&BOOL2=all+of+these\&FLD2=Title+\%28TITP\%29\&GRP2=AND+with+next+set\&SAB3=\&BOOL3=all+of+these\&FLD3=Keyword+Anywhere+\%28GKEY\%29\&PID=q\%40oGsHoIu\%40oGox\%3EJnxNIt\%40oGo\%3C\%3C\%3C\&SEQ=20070131092050\&CNT=50\&HIST=1} } @PHDTHESIS{diem_ebw_2008, author = {Stephanie Josephine Diem}, title = {Investigation of EBW thermal emission and mode-conversion physics in the national spherical torus experiment}, school = {Princeton University}, year = {2008}, note = {{Ph.D.}}, abstract = {{NSTX} is a spherical tokamak {(ST)} that operates with n e up to 10 20 m -3 and B T less than 0.6 T, cutting off low harmonic electron cyclotron {(EC)} waves widely used for electron temperature measurements and {EC} heating and current drive in conventional aspect ratio tokamaks. The electron Bernstein wave {(EBW)} can propagate in {ST} plasmas and is readily absorbed and emitted at {EC} harmonics. Additionally, {EBWs} do not experience a density dependent cutoff. As such, {EBWs} may enable local electron temperature measurements and provide local electron heating and current drive. {EBWs} cannot propagate in vacuum but can couple to electromagnetic waves, so for these applications efficient coupling between the {EBWs} and electromagnetic waves outside the plasma is needed. In this thesis, {EBW} emission via the oblique double mode conversion process to the X- and O-modes {(B-X-O)} is measured with two remotely steered antennas located outside of the vacuum vessel. These emission measurements have been used to determine the {EBW} transmission efficiency for a wide range of plasma conditions. The antennas collect fundamental (8-18 {GHz),} second and third (18-40 {GHz)} harmonic emission. The remote steering capability allowed detailed measurements (as a function of toroidal and poloidal pointing angle) of the {B-X-O} transmission window. Peak L-mode {B-X-O} transmission efficiencies of 90\% and 35\% for fundamental and second harmonic emission, respectively, were measured. The measured and theoretical optimal pointing angles agreed within 5$^\circ$ of the simulated values. Evidence of strong {EBW} collisional damping near the fundamental and second harmonic {B-X-O} conversion region was observed in H-mode discharges, reducing the {B-X-O} transmission efficiency to nearly 0{\textbackslash}\% in some cases. Edge conditioning, via Li evaporation, successfully reduced this {EBW} damping and increased transmission efficiencies to 50-60{\textbackslash}\%, agreeing with {EBW} emission {(EBE)} simulations. These results provide experimental evidence supporting {B-X-O} mode conversion theory and provide verification of an {EBE} simulation code developed at the Czech Institute of Plasma Physics. Additionally, the results presented in this thesis provide the first measurements demonstrating that {EBW} collisional damping can be successfully reduced with edge conditioning. Except for power dependent effects, the physics of {B-X-O} emission and {O-X-B} injection are reciprocal, thus the {B-X-O} mode conversion measurements support the feasibility of {EBW} based heating and current drive experiments for future {ST} devices such as an {ST-based} Component Test Facility. T e {(R)} reconstructions of {ST} H-mode plasma via {EBE} measurements are also presented in this thesis and have been quite difficult. The {B-X-O} process is a complicated process, involving double mode conversion of the emission before it is detected, and an antenna view oblique to the magnetic field near the plasma edge, so that extensive numerical modeling is needed to determine the emission location and reconstruct the T e {(R)} profile. In contrast to stellarators or conventional aspect ratio tokamaks, reconstruction of the magnetic equilibrium in an {ST} is strongly affected by time varying internal currents that generate poloidal fields that can be comparable to the toroidal field. Good agreement with the edge Thomson scattering and {EBE} T e {(R)} measurements have been observed. Inside a major radius of 140 cm, {EBE} T e {(R)} measurements are within 40{\textbackslash}\% of Thomson scattering measurements.}, file = {diem_ebw_2008.pdf:refs/theses/diem_ebw_2008.pdf:PDF}, keywords = {Fluid {dynamics,Gases}}, url = {http://proquest.umi.com/pqdweb?did=1594490231&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @INPROCEEDINGS{diem_te_2006, author = {S. J. Diem and G. Taylor and P. C. Efthimion and B. P. {LeBlanc} and M. Carter and J. Caughman and J. B. Wilgen and R. W. Harvey and J. Preinhaelter and J. Urban}, title = {T_e(R,t) measurements using electron Bernstein wave thermal emission on {NSTX}}, booktitle = {Rev. Sci. Instrum.}, year = {2006}, volume = {77}, pages = {10E919--4}, month = oct, publisher = {AIP}, doi = {10.1063/1.2235112}, keywords = {antennas in plasma,plasma Bernstein waves,plasma diagnostics,plasma electrostatic waves,plasma temperature,plasma toroidal {confinement,Tokamak} devices, EBW, electron Bernstein waves}, url = {http://link.aip.org/link/?RSI/77/10E919/1} } @ARTICLE{dimits_comparisons_2000, author = {A. M. Dimits and G. Bateman and M. A. Beer and B. I. Cohen and W. Dorland and G. W. Hammett and C. Kim and J. E. Kinsey and M. Kotschenreuther and A. H. Kritz and L. L. Lao and J. Mandrekas and W. M. Nevins and S. E. Parker and A. J. Redd and D. E. Shumaker and R. Sydora and J. Weiland}, title = {Comparisons and physics basis of tokamak transport models and turbulence simulations}, journal = {Physics of Plasmas}, year = {2000}, volume = {7}, pages = {969-983}, month = mar, note = {ITG cyclone base case simulation parameters}, doi = {10.1063/1.873896}, keywords = {ITER TOKAMAK,PERFORMANCE,PLASMA INSTABILITY,PLASMA SIMULATION,plasma transport processes,plasma turbulence,THERMONUCLEAR REACTORS,Tokamak devices,TRANSPORT THEORY,TURBULENCE}, url = {http://link.aip.org/link/?PHP/7/969/1} } @ARTICLE{ding_laser_2004, author = {W. X. Ding and D. L. Brower and B. H. Deng and D. Craig and S. C. Prager and V. Svidzinski}, title = {Laser Faraday rotation measurement of current density fluctuations and electromagnetic torque (invited)}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, pages = {3387}, number = {10}, doi = {10.1063/1.1785275}, issn = {00346748}, url = {http://link.aip.org/link/RSINAK/v75/i10/p3387/s1&Agg=doi} } @ARTICLE{ding_measurement_2008, author = {W. X. Ding and D. L. Brower and T. Y. Yates}, title = {Measurement of magnetic fluctuation-induced particle flux (invited)}, journal = {Review of Scientific Instruments}, year = {2008}, volume = {79}, pages = {{10E701}}, number = {10}, doi = {10.1063/1.2953437}, issn = {00346748}, url = {http://link.aip.org/link/RSINAK/v79/i10/p10E701/s1&Agg=doi} } @ARTICLE{dominguez_stabilization_1990, author = {R. R. Dominguez}, title = {Stabilization of collisionless trapped particle modes in tokamaks}, journal = {Physics of Fluids B: Plasma Physics}, year = {1990}, volume = {2}, pages = {2151--2154}, number = {9}, doi = {10.1063/1.859435}, keywords = {{ASPECT} {RATIO,COLLISIONLESS} {PLASMA,ELECTRON} {TEMPERATURE,EQUILIBRIUM,OPTIMIZATION,STABILIZATION,TOKAMAK} {DEVICES,TRAPPEDPARTICLE} {INSTABILITY}}, url = {http://link.aip.org/link/?PFB/2/2151/1} } @ARTICLE{dorf_energy_2009, author = {L. A. Dorf and V. E. Semenov}, title = {Energy flow through a nonambipolar Langmuir sheath}, journal = {Physics of Plasmas}, year = {2009}, volume = {16}, pages = {073501--5}, number = {7}, month = jul, doi = {10.1063/1.3166597}, keywords = {plasma boundary layers, plasma kinetic theory, plasma sheaths, plasma-wall interactions}, url = {http://link.aip.org/link/?PHP/16/073501/1} } @ARTICLE{dorf_electrostatic_2004, author = {L. Dorf and Y. Raitses and N. J. Fisch}, title = {Electrostatic probe apparatus for measurements in the near-anode region of Hall thrusters}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, pages = {1255-1260}, month = may, keywords = {ion engines,plasma density,plasma magnetohydrodynamics,plasma probes,plasma temperature,plasma transport processes}, url = {http://link.aip.org/link/?RSI/75/1255/1} } @ARTICLE{dorf2003, author = {L. Dorf and V. Semenov and Y. Raitses}, title = {Anode sheath in Hall thrusters}, journal = {Applied Physics Letters}, year = {2003}, volume = {83}, pages = {2551--2552}, number = {13}, month = sep, note = {The anode sheath regime depends primarily on the discharge voltage and the mass flow rate, assuming a given electron temperature profile. At moderate discharge voltages, a negative anode sheath accelerates ions toward the channel exit, and accelerates electrons into the anode. As I understand it, the negative (ie. electron sheath) is necessary to overcome the reduced mobility of electrons because of the magnetic field. At large discharge voltages, the electron axial velocity in quasineutral plasma near the anode becomes on the same order as the the electron thermal velocity, rendering the negative ion sheath unnecessary. If at very high discharge voltages the $T_e$ is unchanged, then a positive anode sheath might form, but if it increases, a negative anode sheath may still be necessary. I don't understand that last part; it seems counter-intuitive.}, keywords = {Hall thruster, 1yr_project}, owner = {egranste}, timestamp = {2007.06.26} } @ARTICLE{dorland_electron_2000, author = {W. Dorland and F. Jenko and M. Kotschenreuther and B. N. Rogers}, title = {Electron Temperature Gradient Turbulence}, journal = {Physical Review Letters}, year = {2000}, volume = {85}, pages = {5579}, month = dec, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {The first toroidal, gyrokinetic, electromagnetic simulations of small scale plasma turbulence are presented. The turbulence considered is driven by gradients in the electron temperature. It is found that electron temperature gradient (ETG) turbulence can induce experimentally relevant thermal losses in magnetic confinement fusion devices. For typical tokamak parameters, the transport is essentially electrostatic in character. The simulation results are qualitatively consistent with a model that balances linear and secondary mode growth rates. Significant streamer-dominated transport at long wavelengths occurs because the secondary modes that produce saturation become weak in the ETG limit.}, doi = {10.1103/PhysRevLett.85.5579}, keywords = {etg, gs2}, url = {http://link.aps.org/abstract/PRL/v85/p5579} } @ARTICLE{drake_microtearing_1980, author = {J. F. Drake and N. T. Gladd and C. S. Liu and C. L. Chang}, title = {Microtearing Modes and Anomalous Transport in Tokamaks}, journal = {Physical Review Letters}, year = {1980}, volume = {44}, pages = {994}, number = {15}, month = apr, note = {Copyright (C) 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {Microtearing (high-m) modes driven by the electron temperature gradient are found to be unstable for present tokamak parameters. A self-consistent calculation of the nonlinear saturation of this instability yields magnetic fluctuations {{\textbar}B̃{\textbar}} / B≃ρe / {LT.} The associated crossfield electron thermal conductivity is shown to be inversely proportional to density, consistent with Alcator scaling, and comparable in magnitude with that inferred from experiments.}, doi = {{10.1103/PhysRevLett.44.994}}, url = {http://link.aps.org/abstract/PRL/v44/p994} } @ARTICLE{dunaevsky_rfdischarge_2006, author = {A. Dunaevsky and Y. Raitses and N. J. Fisch}, title = {Plasma acceleration from radio-frequency discharge in dielectric capillary}, journal = {Applied Physics Letters}, year = {2006}, volume = {88}, pages = {251502}, month = {JUN}, note = {Quasineutral plasma flow with energy of several tens of eV generated; potential drop due to plasma expansion at the open end of the capillary and high-$T_e$ electrons in the discharge promote ion acceleration. Acceleration region is outside the capillary with convex shape; large plume angle (65 deg). Ref 14: If the discharge is created in a dielectric chamber with an open end, conservation of total flux leads to a corresponding increase of the wall potential to sustain the voltage drop due to plasma expansion. The potential drop due to expansion is dependent on $T_e$ in the upstream discharge, and high-$T_e$ electrons upstream are required for an energetic plasma flow. In a capacitive RF discharge, the plasma a positive voltage with respect to the electrodes of about 1/3 the RF amplitude, and the diameter of the capillary is smaller than the skin depth of the plasma at the highest density expected in the discharge. Planar probe trace: Ions exist with energies of about 80eV, few below 80eV. The slope of the characteristic below $V_p$ indicates beam electrons of about 20eV. What is ``current-compensated flow'', and why in this regime is $E_i \approx 4.7 E_e$ ? There are also low-temp electrons, and this part of the dist. function is fit with a Druyvestern-type function (ie. $\sim \exp{-aE_e^2}$); and this is typical for ionization in the presence of collisions and E fields, indicating additional ionization is taking place in the downstream region nrear the exit plane where neutral density is still high.}, abstract = {A capacitive rf discharge was demonstrated in a dielectric capillary for generation of quasineutral plasma flow with energies of several tens of eV. A potential gradient at the open end of the capillary and high-temperature electrons in the capillary discharge promote the ion acceleration. The plasma flow was generated from a ceramic capillary with inner diameter of similar to 0.8 mm and a length of similar to 10 mm, at a gas flow rate of 2-10 SCCM (SCCM denotes cubic centimeter per minute at STP) and input power of 15-20 W. The ion energy spectrum consists of high-energy accelerated ions and a low-energy tail formed due to ionization in the acceleration region. The relatively wide plume angle of similar to 65 degrees indicates that the acceleration region is placed outside the capillary and has a convex shape. Estimated total efficiency at 2 SCCM Xe flow rate and 15 W input power reaches 2\%-3\%. This approach may be attractive for micropropulsion applications due to its simplicity, low weight and small dimensions of the source, and the absence of a cathode neutralizer. (c) 2006 American Institute of Physics.}, doi = {10.1063/1.2214127}, keywords = {EXPANSION,FREE DOUBLE-LAYER,THRUSTERS} } @ARTICLE{dushman_thermionic_1930, author = {S. Dushman}, title = {Thermionic emission}, journal = {REVIEWS OF MODERN PHYSICS}, year = {1930}, volume = {2}, pages = {0381-0476}, number = {4}, month = oct, issn = {0034-6861}, keywords = {thermionic emission, 1yr_project} } @ARTICLE{ecrh-group_electron-bernstein-wave_2003, author = {ECRH-Group and H. P. Laqua and H. Maassberg and N. B. Marushchenko and F. Volpe and A. Weller and W. Kasparek}, title = {Electron-Bernstein-Wave Current Drive in an Overdense Plasma at the Wendelstein 7-AS Stellarator}, journal = {Physical Review Letters}, year = {2003}, volume = {90}, pages = {075003}, number = {7}, month = feb, note = {Copyright {(C)} 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {{Electron-Bernstein-wave} {(EBW)} current drive in an overdense plasma was demonstrated at the Wendelstein {7-AS} stellarator for the first time. The {EBWs} were generated by {O-X-B} mode conversion. The relatively high current drive efficiency was consistent with theoretical predictions. The experiments provided first investigations of {EBW} phase space interaction for wave refractive indices much larger than unity.}, doi = {{10.1103/PhysRevLett.90.075003}}, url = {http://link.aps.org/abstract/PRL/v90/e075003} } @INPROCEEDINGS{efthimion_new_1999, author = {P. C. Efthimion and J. C. Hosea and R. Kaita and R. Majeski and G. Taylor}, title = {New electron cyclotron emission diagnostic for measurement of temperature based upon the electron Bernstein wave}, booktitle = {Proceedings of the 12th topical conference on high temperature plasma diagnostics}, year = {1999}, volume = {70}, pages = {1018--1020}, address = {Princeton, New Jersey {(USA)}}, publisher = {AIP}, doi = {10.1063/1.1149464}, keywords = {{BERNSTEIN} {MODE,MAGNETIC} {FIELDS,plasma} Bernstein {waves,PLASMA} {DIAGNOSTICS,plasma} temperature,plasma toroidal {confinement,PLASMA} {WAVES,RADIOMETERS,radiometry,TEMPERATURE} {MEASUREMENT}}, url = {http://link.aip.org/link/?RSI/70/1018/1} } @INPROCEEDINGS{ellis_experiment_2001, author = {R. F. Ellis and A. B. Hassam and S. Messer and B. R. Osborn}, title = {An experiment to test centrifugal confinement for fusion}, booktitle = {The 42nd annual meeting of the division of plasma physics of the American Physical Society and the 10th international congress on plasma physics}, year = {2001}, volume = {8}, pages = {2057-2065}, address = {Quebec City, Quebec (Canada)}, month = may, publisher = {AIP}, journal = {The 42nd annual meeting of the division of plasma physics of the American Physical Society and the 10th international congress on plasma physics}, keywords = {fusion reactor instrumentation,fusion reactor operation,plasma heating,plasma instability,plasma magnetohydrodynamics,plasma simulation,plasma toroidal confinement,plasma transport processes,plasma turbulence}, url = {http://link.aip.org/link/?PHP/8/2057/1} } @ARTICLE{emmert_electric_1980, author = {G. A. Emmert and R. M. Wieland and A. T. Mense and J. N. Davidson}, title = {Electric sheath and presheath in a collisionless, finite ion temperature plasma}, journal = {Physics of Fluids}, year = {1980}, volume = {23}, pages = {803-812}, month = apr, doi = {10.1063/1.863062}, keywords = {ANALYTICAL SOLUTION,BOLTZMANN STATISTICS,COLLISIONLESS PLASMA,DEBYE LENGTH,DISTRIBUTION FUNCTIONS,ELECTRIC POTENTIAL,ELECTRONS,EQUATIONS,ION TEMPERATURE,NUMERICAL SOLUTION,PLASMA DIAGNOSTICS,PLASMA SHEATH}, url = {http://link.aip.org/link/?PFL/23/803/1} } @ARTICLE{engeln_plasma_2002, author = {R.~Engeln and S.~Mazouffre and P.~Vankan and I.~Bakker and D.~C.~Schram}, title = {Plasma expansion: fundamentals and applications}, journal = {Plasma Sources Science and Technology}, year = {2002}, volume = {11}, pages = {A100---A104}, note = {Used supersonic jet theory for a hot neutral gas to model plasma expansion: density model: $n(z)=\frac{n_0}{1+(z/z_0)}$ where $z_0$ is a scale length. Temperature is assumed to be adiabatically related to density, but using a smaller value for the specific heat ratio, because recombination keeps the temperature higher than in neutral gas expansion. The plasma expands and is supersonic until its density drops below the background; then there is a stationary shock, the density jumps up, and the flow is subsonic and beam width stays approximately constant. The maximum speed on axis is modeled to be: $w_max = c_{s0}\sqrt{\frac{\gamma +1}{\gamma -1}}$ and is reached a few diameters after the exit nozzle.}, keywords = {plasma expansion, 1yr_project}, owner = {egranste}, timestamp = {2007.06.27} } @ARTICLE{enloe_high-resolution_1994, author = {CL ENLOE}, title = {HIGH-RESOLUTION RETARDING POTENTIAL ANALYZER}, journal = {REVIEW OF SCIENTIFIC INSTRUMENTS}, year = {1994}, volume = {65}, pages = {507-508}, number = {2}, month = feb, issn = {0034-6748}, keywords = {diagnostics,retarding potential analyzer,RPA, 1yr_project} } @INPROCEEDINGS{ernst_tem_iaea_2006, author = {D.R. Ernst and N. Basse and W. Dorland and C. L. Fiore and L. Lin and A. Long and M. Porkolab and K. Zeller and K. Zhurovich}, title = {Identification of TEM Turbulence through Direct Comparison of Nonlinear Gyrokinetic Simulations with Phase Contrast Imaging Density Fluctuation Measurements}, booktitle = {Proceedings of the 21st IAEA Fusion Energy Conference (Chengdu, China)}, year = {2006}, pages = {TH/1-3}, address = {Vienna}, month = {OCT}, organization = {IAEA}, note = {TEM can be driven by either the electron density or temperature gradient; most relevant when ITG are stable or only weakly unstable. TEM in experiment produce strong particle and electron thermal energy transport as the density gradient and electron temperature increase. NL gyrokinetic simulations of pure TEM turbulence driven by density gradients in (1,2) and temperature gradient in (10,11). Experimental benefits of C-MOD: (1) strong fluctuations in the ITB driven by density gradient allow spatial localization of the chordal PCI density fluc. measurement. (2) no core fueling, ITER-like densities ($2-8\times 10^{14}\mathrm{cm}^{-3}$, and $\sim$1 mm between density spatial channels. They use the Enhanced D$\alpha$ (EDA) H-mode. electron density is determined from CCD visible Bremsstrahlung emission profiles are acquired with sub-ms sampling and $\sim$1 mm spatial sampling (14), usually assuming $Z_{eff}$ is flat. PCI measures wavenumbers $\pm 8.3$cm$^{-1}$, and frequencies 5-300kHz (TEM located 20-80kHz) with 32 vertical laser chords. The beams pass through a phase plate and interfere with a reference beam on a detector array. ``For field-aligned fluctuations, the radius of a laser spot on the detector is prop. to the scatering wavenumber, and its azimuthal location is perp. to the magnetic field.'' PCI: ref. 15: uses 10 MHz sampling, 25 W CO2 laser, 10.6 $\mu$m wavelength; upgraded to $\pm 40$cm$^{-1}$ wavenumber range and 60 W laser. On-axis ICRH increases the temperature in the ITB, and the region with small density gradient scale length expands, strongly destabilizes the TEM inside the ITB. The synthetic diagnostic for PCI in GS2 includes transforming flux coords (assumes a Miller equilibrium, ref. 20, so that the cylindrical $k_R$ is a superposition of $k_\theta$ and $k_\psi$) to cartesian and integrating the density fluctuations over portions of the flux tube viewed by PCI. They make copies of portions of the flux tube (which are more than a correlation length apart) and integrate over this area so that they cover the $R$ distance intersected by PCI. They also include an instrument function to account for the Gaussian beam profile, finite aperture effects, and reduced sensitivity for small $k_R \sim 0$. The $k_\psi$ spectrum is dominated by zonal flows, peaking at $k_psi = 0$. The upgraded collision operator in GS2 adds classical ion diffusion (FLR collisional terms), implemented as a Krook operator with particle and momentum conserving terms. Classical ion diffusion has a strong damping effect on shorter wavelengths. Energy diffusion with momentum and energy conserving terms was implemented fully implicitly. They investigate the parametric upshift of the NL upshift of the TEM critical density gradient: increases with collisionality, and zonal flow is less-dominant above the effective NL threshold. New capability added to localize PCI measurements to the upper or lower half of the plasma cross-section, revealing the mode propagation direction.}, abstract = {Nonlinear gyrokinetic simulations of Trapped Electron Mode (TEM) turbulence have reproduced measured particle fluxes and thermal energy fluxes, within experimental uncertainty, in Alcator C-Mod. This has provided a model for internal transport barrier control with on-axis ICRH in Alcator C-Mod, without adjustable model parameters. The onset of TEM turbulent transport limits the density gradient, preventing radiative collapse. Here we move beyond comparisons of simulated and measured fluxes to a more fundamental and direct comparison with density fluctuation spectra. Using a new synthetic diagnostic, excellent agreement is obtained between wavelength spectra from nonlinear GS2 simulations, and spectra measured by Phase Contrast Imaging. The density fluctuations are associated with the steep density gradient in the C-Mod ITB, which provides spatial localization for the chordal PCI measurement. Gyrokinetic stability analysis shows that Trapped Electron Modes are strongly destabilized inside the ITB foot by the addition of on-axis ICRH. Nonlinear GS2 simulations reproduce the relative increase in fluctuation level when on-axis heating is applied. Further, we have extended the GS2 Lorentz collision operator to include classical diffusion associated with the ion finite Larmor radius, and have implemented collisional energy diffusion, together with particle, momentum, and energy conservation terms. Classical diffusion is shown to strongly stabilize shorter wavelength trapped electron modes for realistic C-Mod collisionalities. A series of detailed nonlinear gyrokinetic simulations show the nonlinear upshift in the TEM critical density gradient increases favorably with collisionality.}, keywords = {trapped electron mode, TEM, phase contrast imaging, PCI, gyrokinetic simulation}, owner = {erikg}, timestamp = {2008.09.26}, url = {http://www-naweb.iaea.org/napc/physics/fec/fec2006/html/node43.htm} } @ARTICLE{ernst_role_2004, author = {D. R. Ernst and P. T. Bonoli and P. J. Catto and W. Dorland and C. L. Fiore and R. S. Granetz and M. Greenwald and A. E. Hubbard and M. Porkolab and M. H. Redi and J. E. Rice and K. Zhurovich and Alcator C-Mod Group}, title = {Role of trapped electron mode turbulence in internal transport barrier control in the Alcator C-Mod Tokamak}, journal = {45th Annual Meeting of the APS Division of Plasma Physics}, year = {2004}, volume = {11}, pages = {2637-2648}, number = {5}, month = may, note = {Off-axis Hydrogen minority ICRH is used to trigger the ITB. ITG modes may be suppressed by shear, or more likely, by a flatter temperature profile that is below the critical gradient. The Ware pinch is sufficient to account for the density rise in the core (no central fueling). Impurities start to build up in the core once the barrier is formed, but then applying on-axis minority ICRH stops the barrier formation and keeps Zeff at 1.8. On-axis ICRH is a means of external control of particle transport of the ITB, and is a means to prevent radiative collapse due to the buildup of impurities in the core. As the density gradient steepens during ITB formation, TEM are driven unstable: linear stability boundary is crossed and the drift wave phase velocity changes to the electron direction, coincident with the $L_{ne}$ reaching steady-state and the computed particle diffusivity ceasing to decrease. Suggest TEM which produce strong particle transport relative to the ITG may limit the density rise in the ITB. On-axis heating increases the linear growth rate even further: which is good for control. Neoclassical calculations were used to infer the poloidal rotation. Shearing rate could only be determined when the toroidal rotation was slow, since its profile was unknown. Artificially turning off the temperature gradient in the linear runs didn't affect the max growth rate in the ITB (showing the mode was driven only by the density gradient) and the mode disappeared when adiabatic electrons were assumed: therefore the mode is associated with trapped electrons. Three types of trapped electrons are discussed: (1) Dissipative TEMs: driven unstable by the nonadiabatic electron response produced by detrapping, with growth rates initially increasing with collision frequency. These were not likely observed, since their growth rates decreased with collisionality and they are only appear for collisionalities higher than those in the experiments. (2) Collisionless TEMs: driven unstable by resonance with the trapped electron toroidal precession drift (ref 47). Qualitatively consistent trends with their simulations: temperature gradients stabilize lower wavelengths (from finite gyroradius downshift of the real freqency refs.2, 48, 53). (3) Nonresonant fluid-like TEM: driven unstable by the trapped electron precession drift in the bad curvature region, proposed to explain electron thermal energy transport. Numerical study in ref. 53. They have a heuristic expression for the ITG/TEM linear growth rate for the fluid-like modes. They map out the stability diagram in terms of the temperature and density gradient scale lengths, and find on-axis heating doesn't affect the critical linear density gradient. Nonlinear simulations find large, infrequent (intermittent) bursts of particle flux throughout the simulation: result from transient suppression and recovery of the zonal flows whose growth rate is proportional to the amplitude of the primary modes (leading to explosive growth) and come from a NL interaction with the primary modes. They also find a nonlinear upshift in the critical density gradient before turbulent diffusion appears. Zonal flow potentials near marginal stability show bursts of energy exchange with the primary mode, lagging bursts in particle flux. They conclude TEM turbulence will limit the density peaking by opposing the Ware pinch once the NL threshold is exceeded. TEM turbulent diffusivites match TRANSP values within experimental uncertainties. They don't include ETG in their calculation: linearly stable inside ITB, unstable outside. On-axis heating increases the temperature inside the ITB, and decreases the collisionality. At these collisionalities, the scaling of the TEM with collisionality is weak, so temperature has the bigger effect: $D^TEM\sim T^{3/2}$ Feedback of the plasma current causes the Ware pinch to decrease somewhat faster than $T^{-1/2}$. They conclude the main mechanism for ITB control with on-axis ICRH is the increase in the TEM turbulent diffusivity due to gyro-Bohm scaling of the turbulent transport and the weaker unfavorable scaling of the Ware pinch. TEM is an effective means of removing impurities without degrading ion thermal energy confinement (since its effect on $\chi_i$ is weak) except through its coupling with the electron energy channel (since its $\chi_e > D_I > D_e > \chi_i$. It is significant that this ITB was formed without reversed magnetic shear which reduces the TEM growth rate by reducing the effective number of trapped electrons in bad curvature (ref. 47). They think it is unlikely that the ITB will form when the current drive is inductive and there is no Ware pinch.}, abstract = {Nonlinear gyrokinetic simulations of trapped electron mode (TEM) turbulence, within an internal particle transport barrier, are performed and compared with experimental data. The results provide a mechanism for transport barrier control with on-axis radio frequency heating, as demonstrated in Alcator C-Mod experiments [S. J. Wukitch et al., Phys. Plasmas 9, 2149 (2002)]. Off-axis heating produces an internal particle and energy transport barrier after the transition to enhanced Dalpha high confinement mode. The barrier foot reaches the half-radius, with a peak density 2.5 times the edge density. While the density profile peaks, the temperature profile remains relatively unaffected. The peaking and concomitant impurity accumulation are controlled by applying modest central heating power late in the discharge. Gyrokinetic turbulence simulations of the barrier formation phase, using the GS2 code [W. Dorland et al., Phys. Rev. Lett. 85, 5579 (2000)] show that toroidal ion temperature gradient driven modes are suppressed inside the barrier foot, but continue to dominate in the outer half-radius. As the density gradient steepens further, trapped electron modes are driven unstable. The onset of TEM turbulence produces an outflow that strongly increases with the density gradient, upon exceeding a new nonlinear critical density gradient, which significantly exceeds the linear critical density gradient. The TEM turbulent outflow ultimately balances the inward Ware pinch, leading to steady state. Moreover, the simulated turbulent particle diffusivity matches that inferred from particle balance using measured density profile data and the calculated Ware pinch. This turbulent diffusivity exhibits a strong unfavorable temperature dependence that allows control with central heating.}, address = {Albuquerque, New Mexico (USA)}, booktitle = {45th Annual Meeting of the APS Division of Plasma Physics}, doi = {10.1063/1.1705653}, keywords = {pinch effect,plasma boundary layers,plasma density,plasma impurities,plasma instability,plasma kinetic theory,plasma radiofrequency heating,plasma simulation,plasma temperature,plasma toroidal confinement,plasma transport processes,plasma turbulence}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/11/2637/1} } @ARTICLE{ernst_role_2009, author = {D. R. Ernst and J. Lang and W. M. Nevins and M. Hoffman and Y. Chen and W. Dorland and S. Parker}, title = {Role of zonal flows in trapped electron mode turbulence through nonlinear gyrokinetic particle and continuum simulation}, journal = {Physics of Plasmas}, year = {2009}, volume = {16}, pages = {055906--7}, number = {5}, month = may, note = {{TEM,} {CTEM}}, doi = {10.1063/1.3116282}, keywords = {plasma flow, plasma instability, plasma kinetic theory, plasma nonlinear processes, plasma simulation, plasma turbulence}, url = {http://link.aip.org/link/?PHP/16/055906/1} } @ARTICLE{erofeev1986ion, author = {Erofeev, V.~I. and Ryutov, D.~D.}, title = {Ion confinement in a mirror system with a small aspect ratio}, journal = {Soviet Journal of Plasma Physics}, year = {1986}, volume = {12}, pages = {670}, keywords = {mirrors, open systems, 2yr_project}, owner = {erikg}, timestamp = {2007.12.06} } @ARTICLE{evans_edge_2006, author = {Todd E. Evans and Richard A. Moyer and Keith H. Burrell and Max E. Fenstermacher and Ilon Joseph and Anthony W. Leonard and Thomas H. Osborne and Gary D. Porter and Michael J. Schaffer and Philip B. Snyder and Paul R. Thomas and Jonathan G. Watkins and William P. West}, title = {Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas}, journal = {Nat Phys}, year = {2006}, volume = {2}, pages = {419--423}, number = {6}, month = jun, doi = {10.1038/nphys312}, issn = {1745-2473}, url = {http://dx.doi.org/10.1038/nphys312} } @ARTICLE{fisch_variable_2001, author = {N. J. Fisch and Y. Raitses and L. A. Dorf and A. A. Litvak}, title = {Variable operation of Hall thruster with multiple segmented electrodes}, journal = {Journal of Applied Physics}, year = {2001}, volume = {89}, pages = {2040-2046}, month = feb, doi = {10.1063/1.1337919}, keywords = {collective accelerators,plasma production}, url = {http://link.aip.org/link/?JAP/89/2040/1} } @ARTICLE{forest_steady-state_1986, author = {Cary Forest and Noah Hershkowitz}, title = {Steady-state ion pumping of a potential dip near an electron collecting anode}, journal = {Journal of Applied Physics}, year = {1986}, volume = {60}, pages = {1295-1299}, keywords = {PLASMA,POTENTIAL BARRIER,POTENTIALS,PUMPING,TRAPPING}, url = {http://link.aip.org/link/?JAP/60/1295/1} } @PHDTHESIS{forest_pressure-driven_1992, author = {Cary Brett Forest}, title = {Pressure-driven currents in the {CDX-U} trapped particle configuration}, school = {Princeton University}, year = {1992}, note = {In the introduction includes information and references to beta limits. Amplitude and phase detector is: Cutsogeorge, G. PPPL report 1623, 1988 digital counter is: Greenberger, A. PPPL report 1466, 1978 "Digital Multiradian phase display circuit"}, comment = {A novel, non-inductive current drive technique has been developed for initiating and maintaining tokamak discharges in {CDX-U:} the current drive experiment-upgrade, a low-aspect-ratio tokamak facility. The new method utilizes naturally occurring internally generated currents which are present in toroidal plasmas. On {CDX-U,} electron cyclotron heating {(ECH)} was used to provide the heating power necessary to create and maintain a high-\${\textbackslash}beta{\textbackslash}sb{pol}\$ plasma, the plasma for which self-generated currents are significant. A novel poloidal field configuration provided initial confinement for an {ECH} produced, trapped electron population. The {ECH} power, injected through a simple (non-phased) waveguide, was well suited to produce a hot, low-collisionality electrons needed for current generation. With application of {ECH,} internal plasma generated currents occurred spontaneously and increased with applied {ECH} power. The generated current scaled inversely with neutral particle density, showing the importance of reducing the plasma collisionality. The current direction depended only on the poloidal field direction, not on the toroidal field direction. The currents flowing into segmented limiters were found to be very small, confirming that the currents were internally generated. With application of \${\textbackslash}sim\$8 {kW} of {ECH} power, a toroidal plasma current of up to 1200 A was generated. At this plasma current level, the poloidal fields from the plasma currents were sufficiently large to form a low-aspect-ratio tokamak plasma, demonstrated unambiguously by poloidal field reversal on the inner wall of the vessel. The \${\textbackslash}beta{\textbackslash}sb{pol}\$ in this experiment was high, \${\textbackslash}epsilon{\textbackslash}beta{\textbackslash}sb{pol}{\textbackslash}simeq 1\$, consistent with the observed pressure driven currents. Furthermore, the normalized collisionality--the ratio of the electron bounce period to collision time--was less than one in regions of strong current density; thus, the observed currents were consistent with theoretical predictions of trapped particle generated currents. This result demonstrated that it is possible to generate plasma currents, even when the magnetic topology is changing. In {CDX-U,} the equilibrium evolved from an open field line configuration to a closed field line tokamak configuration. The result opens up the possibility of creating and maintaining tokamak plasmas solely by internally generated currents.}, keywords = {Energy,Fluid dynamics,Gases}, url = {http://proquest.umi.com/pqdweb?did=747632661&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @ARTICLE{forest_cdx-u_1990, author = {C. B. Forest and G. Greene and M. Ono}, title = {CDX-U two-dimensional scanning microwave system}, journal = {Eighth topical conference on hightemperature plasma diagnostics}, year = {1990}, volume = {61}, pages = {2888-2890}, month = oct, abstract = {A versatile 2 mm scanning interferometer has been built for the CDX-U machine. The unique diagnostic access of CDX-U allows a vertical view through windows on the top and bottom, and a two-pass horizontal view through a side window which utilizes reflection off of a mirror mounted on the center column of the vessel. A single launching antenna and two separate receivers can be operated in a variety of modes including simple interferometry, polarimetry, and scattering. The optics, mechanical translation system, and 2 mm heterodyne receiver are described. Review of Scientific Instruments is copyrighted by The American Institute of Physics.}, doi = {10.1063/1.1141764}, keywords = {ANTENNAS,CURRENT DRIVE HEATING,FARADAY EFFECT,interferometer,MICROWAVE EQUIPMENT,PLASMA DENSITY,PLASMA DIAGNOSTICS,scattering diagnostic}, url = {http://link.aip.org/link/?RSI/61/2888/1} } @BOOK{friedplasmadispersionfunction, title = {Plasma Dispersion Function}, publisher = {Academic Press}, year = {1961}, author = {Fried and Conte}, keywords = {GPP2, plasma dispersion function, Z function}, owner = {erikg}, timestamp = {2007.05.09} } @ARTICLE{fruchtman_electric_2006, author = {A. Fruchtman}, title = {Electric field in a double layer and the imparted momentum}, journal = {PHYSICAL REVIEW LETTERS}, year = {2006}, volume = {96}, number = {6}, month = feb, issn = {0031-9007}, keywords = {double layer, 1yr_project} } @ARTICLE{fruchtman05, author = {A. Fruchtman}, journal = PRL, year = {2005}, volume = {96}, pages = {65002}, file = {\\Docs\\Double Layers\\fruchtman06.pdf:\\Docs\\Double Layers\\fruchtman06.pdf:PDF}, keywords = {double layers, 1yr_project} } @ARTICLE{fruchtman_plasma_2006, author = {A. Fruchtman and A. Cohen-Zur}, title = {Plasma lens and plume divergence in the Hall thruster}, journal = {Applied Physics Letters}, year = {2006}, volume = {89}, pages = {111501-3}, keywords = {aerospace propulsion,electric propulsion,ionisation,plasma accelerators,plasma magnetohydrodynamics,plasma transport processes}, url = {http://link.aip.org/link/?APL/89/111501/1} } @ARTICLE{furno_new_2005, author = {I. Furno and H. Weisen and C. Carey and C. Angioni and R. Behn and E. Fable and A. Zabolotsky and the TCV team and JET-EFDA Contributors}, title = {A new method for the inversion of interferometry data using basis functions derived from singular value decomposition of local measurements in tokamak plasmas}, journal = {Plasma Physics and Controlled Fusion}, year = {2005}, volume = {47}, pages = {49-69}, abstract = {A novel method for inverting time-resolved line-integrated interferometric plasma density measurements is described. The method uses singular value decomposition of local density profiles from Thomson scattering measurements obtained at low sampling rates in the same or equivalent plasmas to determine a set of orthogonal spatial basis functions which is well adapted to the physical processes under investigation. The sought-for density profile is expanded into a limited series of these functions and a solution is calculated by using a simple least-squares fit method. The new method overcomes the difficulties encountered with other methods, such as regularization methods, which smoothen gradients and depend on the availability of accurate measurements in the plasma edge region. The small number of computations required provides for a fast algorithm. This method, which combines the high bandwidth of interferometer systems with the spatial accuracy of Thomson scattering, is applied to invert interferometer measurements in a wide variety of operational regimes in the Tokamak {\`a} Configuration Variable and Joint European Torus (JET) tokamaks. In particular, the collisionality dependence of density peaking observed in ASDEX Upgrade is confirmed in JET H-modes using this method.}, doi = {10.1088/0741-3335/47/1/004}, issn = {0741-3335}, url = {http://www.iop.org/EJ/abstract/0741-3335/47/1/004/} } @ARTICLE{furth_finite-resistivity_1963, author = {Harold P. Furth and John Killeen and Marshall N. Rosenbluth}, title = {Finite-Resistivity Instabilities of a Sheet Pinch}, journal = {Physics of Fluids}, year = {1963}, volume = {6}, pages = {459--484}, number = {4}, note = {linear tearing mode}, doi = {10.1063/1.1706761}, keywords = {tearing mode, resistivity}, publisher = {AIP}, url = {http://link.aip.org/link/?PFL/6/459/1} } @ARTICLE{furth_tearing_1973, author = {H. P. Furth and P. H. Rutherford and H. Selberg}, title = {Tearing mode in the cylindrical tokamak}, journal = {Physics of Fluids}, year = {1973}, volume = {16}, pages = {1054-1063}, month = jul, url = {http://link.aip.org/link/?PFL/16/1054/1} } @ARTICLE{garbet_introduction_2004, author = { X Garbet}, title = {Introduction to drift wave turbulence modeling}, journal = {Fusion Science and Technology}, year = {2004}, volume = {45}, pages = {354-361}, month = mar, abstract = {This tutorial presents the techniques that are used to build a transport model from turbulence simulations. Achievements and limitations are reviewed. The main mechanisms leading to an improved confinement are also addressed. The results of turbulence modelling regarding this issue are assessed.}, issn = {1536-1055}, url = {http://www.carolusmagnus.net/papers/2005/papers\_2005.html} } @ARTICLE{gates_plasma_2006, author = {D.A. Gates and J.R. Ferron and M. Bell and T. Gibney and R. Johnson and R.J. Marsala and D. Mastrovito and J.E. Menard and D. Mueller and B. Penaflor and S.A. Sabbagh and T. Stevenson}, title = {Plasma shape control on the National Spherical Torus Experiment (NSTX) using real-time equilibrium reconstruction}, journal = {Nuclear Fusion}, year = {2006}, volume = {46}, pages = {17-23}, abstract = {Plasma shape control using real-time equilibrium reconstruction has been implemented on the National Spherical Torus Experiment (NSTX). The rtEFIT code originally developed for use on DIII-D was adapted for use on NSTX. The real-time equilibria provide calculations of the flux at points on the plasma boundary, which are used as input to a shape control algorithm known as isoflux control. The flux at the desired boundary location is compared with a reference flux value, and this flux error is used as the basic feedback quantity for the poloidal field coils on NSTX. The hardware that comprises the control system is described, as well as the software infrastructure. Examples of precise boundary control are also presented.}, doi = { 10.1088/0029-5515/46/1/002}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/46/1/002} } @ARTICLE{gates_progress_2007, author = {D.A. Gates and J. Menard and R. Maingi and S. Kaye and S.A. Sabbagh and S. Diem and J.R. Wilson and M.G. Bell and R.E. Bell and J. Ferron and E.D. Fredrickson and C.E. Kessel and B.P. LeBlanc and F. Levinton and J. Manickam and D. Mueller and R. Raman and T. Stevenson and D. Stutman and G. Taylor and K. Tritz and H. Yu and the NSTX Research Team}, title = {Progress towards steady state at low aspect ratio on the National Spherical Torus Experiment (NSTX)}, journal = {Nuclear Fusion}, year = {2007}, volume = {47}, pages = {1376-1382}, abstract = {Modifications to the plasma control capabilities and poloidal field coils of the National Spherical Torus Experiment (NSTX) have enabled a significant enhancement in shaping capability which has led to the transient achievement of a record shape factor (S [?] q95 (Ip/a Bt)) of [?]41 (MA m[?]1 T[?]1) simultaneous with a record plasma elongation of k [?] b/a [?] 3. This result was obtained using isoflux control and real-time equilibrium reconstruction. Achieving high shape factor together with tolerable divertor loading is an important result for future ST burning plasma experiments as exemplified by studies for future ST reactor concepts, as well as neutron producing devices, which rely on achieving high shape factors in order to achieve steady state operation while maintaining MHD stability. Statistical evidence is presented which demonstrates the expected correlation between increased shaping and improved plasma performance. Plasmas with high shape factor have been sustained for pulse lengths which correspond to tpulse = 1.6s [?] 50 tE [?] 5 tCR, where tCR is the current relaxation time and tE is the energy confinement time. Plasmas with higher bt [?] 20\% have been sustained for tpulse = 1.2s [?] 25 tE [?] 3 tCR with non-inductive current fractions fNI [?] 50\%, with [?]40\% pressure driven current and [?]10\% neutral beam driven current. An interesting feature of these discharges is the observation that the central value of the safety factor q(0) remains elevated and constant for several current diffusion times without sawteeth, similar to the 'hybrid mode'. Calculations of the profiles of inductive and non-inductive current are compared with measurements of the total current profile and are shown to be in quantitative agreement. Results are shown from experiments which investigate the applicability of high harmonic fast waves (HHFWs) and electron Bernstein waves (EBWs) as current drive and heating sources, and the possibility of LHCD for future ST devices is raised. A calculated scenario which provides 100\% non-inductive current drive is described. NSTX operates with peak divertor heat fluxes which are in the same range as those expected for the ITER device, i.e. with P\_\{\{\\rm heat\}\_\{\\max\}\} \\sim 10\\,\{\\rm MW\}\\,\{\\rm m\}\^\{-2\} . High triangularity, high elongation plasmas on NSTX have been demonstrated to have reduced peak heat flux to the divertor plates to <3 MW m[?]2.}, doi = { 10.1088/0029-5515/47/9/040}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/47/9/040} } @ARTICLE{gates_high_2003, author = {{D.A.} Gates}, title = {High beta, long pulse, bootstrap sustained scenarios on the National Spherical Torus Experiment {(NSTX)}}, journal = {Physics of Plasmas}, year = {2003}, volume = {10}, pages = {1659--1664}, number = {5}, month = may, note = {ion neoclassical confinement}, doi = {10.1063/1.1556606}, keywords = {plasma temperature, plasma toroidal confinement, plasma transport processes, plasma-wall interactions}, url = {http://link.aip.org/link/?PHP/10/1659/1} } @BOOK{collinsnumericalbook, title = {Fundamental Numerical Methods and Data Analysis}, publisher = {NASA ADS}, year = {2003}, author = {George W. Collins, II.}, owner = {egranste}, timestamp = {2007.04.05}, url = {http://ads.harvard.edu/books/1990fnmd.book/} } @ARTICLE{goebel_hollow_2005, author = {DM Goebel and KK Jameson and RM Watkins and I. Katz and IG Mikellides}, title = {Hollow cathode theory and experiment. I. Plasma characterization using fast miniature scanning probes}, journal = {Journal of Applied Physics}, year = {2005}, volume = {98}, pages = {113302}, month = dec, note = {Measured spatial variation of $n$, $V_p$, $T$ with small probes to avoid perturbing the plasma. At 10--25A with a 1.5 cm hollow-cathode, $n \gt \sim 10^{14} \textrm{cm^{-3}}$, with peak inside orifice, $V_p$ on axis inside is 10--20V, $T_e$: 2--5 eV. Steep potential rise of 10V observed in orifice region (bright plasma ball)}, abstract = {A detailed study of the spatial variation of plasma density, temperature, and potential in hollow cathodes using miniature fast scanning probes has been undertaken in order to better understand the cathode operation and to provide benchmark data for the modeling of the cathode performance and life described in a companion paper. Profiles are obtained throughout the discharge and in the very high-density orifice region by pneumatically driven Langmuir probes, which are inserted directly into the hollow cathode orifice from either the upstream insert region inside the hollow cathode or from the downstream anode-plasma region. A fast transverse-scanning probe is also used to provide radial profiles of the cathode plume as a function of position from the cathode exit. The probes are extremely small to avoid perturbing the plasma; the ceramic tube insulator is 0.05 cm in diameter with a probe tip area of 0.002 cm(2). A series of current-voltage characteristics are obtained by applying a rapid sawtooth voltage wave form to the probe as it is scanned through the plasma at speeds of up to 2 m/s to produce the profiles with a spatial resolution of about 0.05 cm. At discharge currents of 10-25 A from the 1.5-cm-diameter hollow cathode, the plasma density inside the cathode is found to exceed 10(14) cm(-3), with the peak density occurring upstream of the orifice. The plasma potentials on axis inside the cathode are found to be in the 10-20 V range with electron temperatures of 2-5 eV, depending on the discharge current and gas flow rate. A potential discontinuity or double layer of less than 10 V is observed in the orifice region, and under certain conditions appears in the bright "plasma ball" in front of the cathode. This structure tends to change location and magnitude with discharge current, gas flow, and orifice size. A potential maximum proposed in the literature to exist in or near the cathode orifice is not observed. Instead, the plasma potential increases from the orifice exit both radially and axially over several centimeters to values of 5-10 V above the anode voltage. The potential and temperature profiles inside the cathode are insensitive to anode configuration changes that alter the discharge voltage at a given flow. Application of an axial magnetic-field characteristic of the cathode region found in ring-cusp ion thrusters increases the plasma density in the cathode plume, but does not significantly change the potential or temperature. Measurements of the plasma profiles and the internal cathode parameters for a hollow cathode operating at discharge currents of up to 25 A in xenon are shown and discussed. (c) 2005 American Institute of Physics.}, doi = {10.1063/1.2135417}, keywords = {hollow cathode discharge} } @ARTICLE{goldston_energy_1984, author = {Robert J. Goldston}, title = {Energy confinement scaling in Tokamaks: some implications of recent experiments with Ohmic and strong auxiliary heating}, journal = {Plasma Physics and Controlled Fusion}, year = {1984}, volume = {26}, pages = {87--103}, number = {1A}, abstract = {Recent results from confinement scaling experiments on tokamaks with Ohmic and strong auxiliary heating are reviewed. An attempt is made to draw these results together into a "low-density" ohmic confinement scaling law, and a scaling law for confinement with auxiliary heating. The auxiliary heating confinement law may also serve to explain the saturation in {TE} vs. ne observed in some ohmic heating density scaling experiments.}, issn = {0741-3335}, keywords = {journal club}, url = {http://www.iop.org/EJ/abstract/0741-3335/26/1A/308/} } @ARTICLE{gopinath_multipactor_1998, author = {V. P. Gopinath and J. P. Verboncoeur and C. K. Birdsall}, title = {Multipactor electron discharge physics using an improved secondary emission model}, journal = {Physics of Plasmas}, year = {1998}, volume = {5}, pages = {1535-1540}, month = may, doi = {10.1063/1.872811}, keywords = {discharges (electric),electron avalanches,high-frequency discharges,plasma simulation,secondary electron emission,space charge}, url = {http://link.aip.org/link/?PHP/5/1535/1} } @ARTICLE{gorelenkov_threshold_1996, author = {N. N. Gorelenkov and R. V. Budny and Z. Chang and M. V. Gorelenkova and L. E. Zakharov}, title = {A threshold for excitation of neoclassical tearing modes}, journal = {Physics of Plasmas}, year = {1996}, volume = {3}, pages = {3379--3385}, number = {9}, doi = {10.1063/1.871614}, keywords = {magnetic islands, bootstrap current, neoclassical transport theory, tokamak, tearing instability}, url = {http://link.aip.org/link/?PHP/3/3379/1} } @ARTICLE{graca_localization_2007, author = {S. da Graca and G. D. Conway and P. Lauber and M. Maraschek and D. Borba and S. Gunter and L. Cupido and K. Sassenberg and F. Serra and M. E. Manso and the {CFN} reflectometry group and the {ASDEX} Upgrade Team}, title = {Localization of {MHD} and fast particle modes using reflectometry in {ASDEX} Upgrade}, journal = {Plasma Physics and Controlled Fusion}, year = {2007}, volume = {49}, pages = {1849--1872}, number = {11}, note = {Explains correlation and coherence analysis. Makes time-frequency plots (spectrogram) by taking {FFT} of 512 points with 50\% overlap sampling. {(Ref.} 24) Also explains relation between relative phase shift and density fluctuation for {MHD} modes {(Ref.28-30,} 32).}, abstract = {The radial structure of toroidal Alfven eigenmodes {(TAEs)} is of great importance for comparison with theoretical predictions. A dual-channel fast frequency hopping millimeter-wave reflectometer installed on the {ASDEX} Upgrade tokamak is capable of measuring density fluctuations from the plasma edge to core, allowing the radial eigenfunction of n = 4 {TAE} and edge {MHD} modes to be obtained using phase perturbation and coherence data analysis techniques. The two techniques reveal similar results, and in particular the radial structure of the n = 4 {TAE} is found to be in good agreement with numerical predictions from linear gyrokinetic simulations. The first results of the radial localization of Alfven cascades are also presented.}, issn = {0741-3335}, keywords = {alfven eigenmodes,fast particle modes,fluctuations,reflectometry,signal processing}, url = {http://www.iop.org/EJ/abstract/0741-3335/49/11/007} } @ARTICLE{granstedt_cathode_2008, author = {E. M. Granstedt and Y. Raitses and N. J. Fisch}, title = {Cathode effects in cylindrical Hall thrusters}, journal = {Journal of Applied Physics}, year = {2008}, volume = {104}, pages = {103302--5}, number = {10}, month = nov, doi = {10.1063/1.2999343}, keywords = {glow discharges,hall thruster,hollow cathode,plasma devices,plasma heating}, url = {http://link.aip.org/link/?JAP/104/103302/1} } @PHDTHESIS{gray_demonstration_2008, author = {Timothy Garrett Gray}, title = {Demonstration of low recycling on a spherical torus with lithium plasma facing components}, school = {Princeton University}, year = {2008}, note = {Ph.D.}, comment = {Plasma facing components {(PFCs)} play an important role in the performance of fusion research devices. In order to investigate the effects of liquid lithium plasma facing components on plasma performance, the Current Drive Experiment - Upgrade {(CDX-U)} spherical torus installed a toroidal liquid lithium tray limiter and an electron beam lithium evaporation system. Measurements of the effective particle confinement time, {[Special} characters omitted.] , were performed by using transient gas puffing and observing the time dependence of the plasma density with microwave interferometry. A significant drop in {[Special} characters omitted.] was observed in the discharges with liquid lithium {PFCs,} which is consistent with increased particle pump-put. Spectroscopic measurements also support an overall decrease in the particle flux to the plasma. In order to look at the global particle balance in the {CDX-U} discharges with liquid lithium {PFCs,} modeling of the plasma discharges with {DEGAS2,} a neutral particle transport code, has been performed. Utilizing the available spectroscopic data, this modeling allows a calculation of a global recycling coefficient ( R ) for both standard discharges and ones with liquid lithium {PFCs.} The modeling shows a significant reduction in recycling, with R = 0.75 in the liquid lithium case. An analysis of the impact of light reflections on the spectroscopic measurements was also performed.}, file = {:refs/theses/gray_low-recycling_2008.pdf:PDF}, keywords = {Fluid {dynamics,Gases}}, url = {http://proquest.umi.com/pqdweb?did=1467898401&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @BOOK{guckenheimer_nonlinear_2002, title = {Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields}, publisher = {Springer}, year = {2002}, author = {John Guckenheimer and Philip Holmes}, pages = {459}, address = {New York}, edition = {Corr. 7th print.}, isbn = {0387908196}, keywords = {Bifurcation theory,Differentiable dynamical systems,Nonlinear oscillations,Vector fields} } @BOOK{hablanianVacuum, title = {High Vacuum Technology: A practical guide}, author = {Hablanian}, owner = {egranste}, timestamp = {2007.10.03} } @ARTICLE{PhysRev.104.672, author = {Hagstrum, Homer D.}, title = {Auger Ejection of Electrons from Molybdenum by Noble Gas Ions}, journal = {Phys. Rev.}, year = {1956}, volume = {104}, pages = {672--683}, number = {3}, month = {Nov}, doi = {10.1103/PhysRev.104.672}, keywords = {secondary electron emission, 1yr_project}, numpages = {11}, publisher = {American Physical Society} } @ARTICLE{PhysRev.96.325, author = {Hagstrum, Homer D.}, title = {Auger Ejection of Electrons from Tungsten by Noble Gas Ions}, journal = {Phys. Rev.}, year = {1954}, volume = {96}, pages = {325--335}, number = {2}, month = {Oct}, doi = {10.1103/PhysRev.96.325}, keywords = {secondary electron emission, 1yr_project}, numpages = {10}, publisher = {American Physical Society} } @ARTICLE{1956PhRv..104..309H, author = {{Hagstrum}, H.~D.}, title = {{Metastable Ions of the Noble Gases}}, journal = {Physical Review }, year = {1956}, volume = {104}, pages = {309-316}, month = oct, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1956PhRv..104..309H}, doi = {10.1103/PhysRev.104.309}, keywords = {1yr_project} } @ARTICLE{1956PhRv..104..317H, author = {{Hagstrum}, H.~D.}, title = {Auger Ejection of Electrons from Tungsten by Noble Gas Ions}, journal = {Physical Review }, year = {1956}, volume = {104}, pages = {317-318}, month = oct, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1956PhRv..104..317H}, doi = {10.1103/PhysRev.104.317}, keywords = {1yr_project} } @ARTICLE{hahm89, author = {Hahm and {W. Tang}}, journal = {Physics of Fluids B}, year = {1989}, volume = {1}, pages = {1185}, keywords = {GPP2, ITG mode, Ion Temperature Gradient, sheared slab analysis, resonances}, owner = {erikg}, timestamp = {2007.05.09} } @ARTICLE{hammett_developments_1993, author = {G. W. Hammett and M. A. Beer and W. Dorland and S. C. Cowley and S. A. Smith}, title = {Developments in the gyrofluid approach to Tokamak turbulence simulations}, journal = {Plasma Physics and Controlled Fusion}, year = {1993}, volume = {35}, pages = {973-985}, abstract = {A status report is given on developments in the gyrofluid approach to simulating tokamak turbulence. 'Gyrofluid' (r 'gyro-Landau fluid') equations attempt to extend the range of validity of fluid equations to a more collisionless regime typical of tokamaks, by developing fluid models of important kinetic effects such as Landau-damping and gyro-orbit averaging. The fluid moments approach should converge if enough moments are kept, though this may require a large number of moments for some processes. Toroidal gyrofluid equations have been extended from 4 to 6 moments, and to include the mu Del B magnetic mirroring force. An efficient field-line coordinate system for toroidal turbulence simulations (useful for both particle and fluid simulations) is presented. Nonlinear 3-D simulations of toroidal ITG-driven turbulence indicate that turbulence-generated sheared flows play an important role in the development and saturation of the turbulence. There is a strong enhancement of the flows when the electrons are assumed adiabatic on each flux surface, which is partially offset by toroidal drift effects which reduce the flows.}, doi = {10.1088/0741-3335/35/8/006}, issn = {0741-3335}, keywords = {recurrence_project}, url = {http://www.iop.org/EJ/abstract/0741-3335/35/8/006/} } @TECHREPORT{hanson_bayesian_1989, author = {K. Hanson}, title = {A Bayesian approach to nonlinear inversion: Abel inversion from x-ray data}, year = {1989}, shorttitle = {A Bayesian approach to nonlinear inversion}, url = {http://citeseer.ist.psu.edu/hanson89bayesian.html} } @ARTICLE{hariharan_modified_2004, author = {P. Hariharan and Andal Narayanan}, title = {Modified pinhole spatial filter producing a clean flat-topped beam}, journal = {Optics \& Laser Technology}, year = {2004}, volume = {36}, pages = {151--153}, number = {2}, month = mar, abstract = {The expanded beam from a laser has a sharply peaked intensity profile. As a result, in many applications where uniform illumination of an extended field is required, it is only possible to use the central part of the beam. We show that if the pinhole normally used to spatially filter the beam is replaced by an annular phase mask, it should be possible to obtain a clean beam providing very nearly uniform illumination over an extended area, with a minimal loss of light.}, doi = {10.1016/j.optlastec.2003.07.006}, issn = {0030-3992}, url = {http://www.sciencedirect.com/science/article/B6V4H-49P48J7-2/2/6599e3845311d31462c17018c3c539a3} } @ARTICLE{la_haye_neoclassical_2006, author = {R. J. La Haye}, title = {Neoclassical tearing modes and their control}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {055501-18}, month = may, keywords = {metastable states,plasma nonlinear processes,plasma pressure,plasma toroidal confinement,plasma transport processes,sawtooth instability,tearing instability,Tokamak devices}, url = {http://link.aip.org/link/?PHP/13/055501/1} } @ARTICLE{hazeltine_self-consistent_1989, author = {R. D. Hazeltine}, title = {Self-consistent radial sheath}, journal = {Physics of Fluids B: Plasma Physics}, year = {1989}, volume = {1}, pages = {2031-2039}, month = oct, doi = {10.1063/1.859067}, keywords = {BOUNDARY LAYERS,COULOMB FIELD,ELECTRON TEMPERATURE,END EFFECTS,GUIDINGCENTER APPROXIMATION,IONS,LIMITERS,PLASMA CONFINEMENT,PLASMA DENSITY,PLASMA SHEATH,TOKAMAK DEVICES,TRAJECTORIES}, url = {http://link.aip.org/link/?PFB/1/2031/1} } @ARTICLE{hazeltine_gyrosheath_1993, author = {R. D. Hazeltine and H. Xiao and P. M. Valanju}, title = {Gyrosheath near the tokamak edge}, journal = {Physics of Fluids B: Plasma Physics}, year = {1993}, volume = {5}, pages = {4011-4014}, month = nov, keywords = {BANANA REGIME,CURVATURE,ELECTRIC DIPOLE MOMENTS,ELECTRIC FIELDS,ELECTRON DENSITY,ION DENSITY,PLASMA CONFINEMENT,PLASMA SHEATH,TOKAMAK DEVICES}, url = {http://link.aip.org/link/?PFB/5/4011/1} } @ARTICLE{helander_two-dimensional_1994, author = {P. Helander and Peter J. Catto}, title = {Two-dimensional kinetic modeling of a tokamak scrape-off layer with recycling}, journal = {Physics of Plasmas}, year = {1994}, volume = {1}, pages = {2213-2219}, month = jul, keywords = {BOUNDARY CONDITIONS,DIFFUSION,DIVERTORS,KINETIC EQUATIONS,LIMITERS,PLASMA POTENTIAL,PLASMA SCRAPEOFF LAYER,PLASMAWALL INTERACTIONS,TOKAMAK DEVICES,WALL EFFECTS}, url = {http://link.aip.org/link/?PHP/1/2213/1} } @ARTICLE{hershkowitz_sheaths_2005, author = {N. Hershkowitz}, title = {Sheaths: More complicated than you think}, journal = {PHYSICS OF PLASMAS}, year = {2005}, volume = {12}, pages = {055502}, number = {5}, month = may, note = {Electron sheaths can only exist if $A_i/A_e \geq \approx \sqrt{m_i/m_e}$ (assuming no SEE from the surfaces and no potential dip through the electron sheath), to balancee- and ion losses and prevent build-up of charge in the plasma. This limits the size of electron sheaths, and requires for large A_e, ion sheaths to be formed instead (ie. pulls the plasma potential up). collisionless cold-ion sheath: Plug $J=en_i(x)v_i(x)$ into Poisson's equation, and use conservation of energy to get an equation for $\phi(x)$ and its derivatives only. Multiply by $d\phi /dx$ and integrate twice to get the Child-Langmuir law: $J=\frac{4\epsilon_0}{9}\sqrt{\frac{2e}{m}}\frac{V^{3/2}}{x^2}$. Since density is not infinite at the sheath edge, initial velocity is necessary: $v_s = c_s = \sqrt{(\gamma_i T_i +T_e)/m_i}$. This is found by assuming the electrons have a Boltzman response, then combining this expression with the ion fluid equations. In the ion sheath, the plasma potential has negative curvature ($n_i \geq n_e$). The sheath thickness is: $\frac{s}{\lambda_D}=\frac{0.79}{\sqrt{\alpha_i}\left(\frac{eV_0}{T_e}\right)^{3/4}}$. Collisions increase the length of the sheath above the ``Child-Langmuir'' value. Presheath: In a collisionless presheath, e*\Delta phi = -T_e/2 is necessary for ions to be acclelerated to v_{Bohm}. Therefore: $n_s = n_0*exp{e*\Delta phi/T_e} = 0.61*n_0$ is the density at the sheath edge. The value of the electric field at the sheath/presheath boundary is nontrivial. Collisionless Electron sheaths: The random electron current to the sheath edge is: $J_{0e}=\alpha_e \frac{n_{0ee}}{4}\sqrt{\frac{8T_e}{\pi m_e}}$, which when inserted into the equation for the Child-Langmuir sheath thickness, gives the same form, with a numerical factor of 0.32. The manner to derive the current through the sheath is different for ions and electrons, because the electrons are not cold, nor are they assumed to be collisionless. A potential dip will often form between the bulk plasma and e- sheathto reduce the e- sheath current density, and this dip acts as a ``virtual cathode''. Figure 10 shows an ion sheath for a large loss area, and an electron sheath for a small loss area. Figure 14 the electrode is at 0, and the wall at about 7cm is grounded, that is why when an rf signal is applied to the electrode, different sheaths are generated at the electrode but not the far wall. The above analysis doesn't work when: $T_i$ is not much less than $T_e$; in this case kinetic treatment of the ions is necessary. Electrons are not Maxwellian; then the Boltzman factor cannot be used and it is necessary to determine the electron response kinetically. In electronegative gasses; electron attachment is important. Ions are collisional; transport is mobility-limited rather than inertia-limited.}, doi = {10.1063/1.1887189}, issn = {1070-664X}, keywords = {bohm criterion, cathode, collisions, double layers, emissive probes, presheath, sheath, 1yr_project} } @ARTICLE{hinton_kinetic_1974, author = {F. L. Hinton and R. D. Hazeltine}, title = {Kinetic theory of plasma scrape-off in a divertor tokamak}, journal = {Physics of Fluids}, year = {1974}, volume = {17}, pages = {2236-2240}, month = dec, note = {Ions: hot, collisionless \$\\nu\_i \\tau\_\\par << 1\$ implies IEDF is almost constant over an orbit, electrons: cold, collisional \$\\nu\_i \\tau\_\\par >> 1\$ Treats effect of separatrix, ignores backstreaming, SEE. }, keywords = {2yr\_project, SOL}, url = {http://link.aip.org/link/?PFL/17/2236/1} } @ARTICLE{hintonhazeltine76, author = {{Hinton}, F.~L. and {Hazeltine}, R.~D.}, title = {Theory of plasma transport in toroidal confinement systems}, journal = {Reviews of Modern Physics}, year = {1976}, volume = {48}, pages = {239-308}, month = apr, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1976RvMP...48..239H}, doi = {10.1103/RevModPhys.48.239}, keywords = {GPP2, tokamak, review} } @ARTICLE{hobbswesson67, author = {{Hobbs, G.D.} and {Wesson, J.A.}}, title = {Heat flow though a Langmuir sheath in presence of electron emission}, journal = {Plasma Physics}, year = {1967}, volume = {9}, pages = {85-87}, number = {1}, abstract = {The steady state electrostatic sheath which forms between a plasma and a wall in order to prevent a net flow of current (LANGMUIR and TONKS, 1929) also acts as a thermal insulator between the hot electrons and the wall (HOBBS and SPALDING19, 66). Such an effect is of interest since it could limit the rate at which energy is lost by thermal conduction along field lines from openendedmapetic traps. The purpose of this note is to calculate the heat flow through the sheath and to demonstrate the effects of electrons emitted by the wall. A more extensive discussion is given elsewhere (HOBBS and WESSON, 1966).}, owner = {egranste}, timestamp = {2007.05.07} } @ARTICLE{hofer_high-isp_2006, author = {Richard R. Hofer AND Robert S. Jankovsky AND Alec D. Gallimore}, title = {High-Specific Impulse Hall Thrusters, Part 1: Influence of Current Density and Magnetic Field}, journal = {Journal of Propulsion and Power}, year = {2006}, volume = {22}, pages = {732--740}, number = {4}, note = {0748-4658}, keywords = {Hall thruster, 1yr_project}, owner = {erikg}, timestamp = {2008.03.31}, url = {http://www.aiaa.org/content.cfm?pageid=318} } @INPROCEEDINGS{hofer_cathode_plume_2006, author = {Hofer, Richard R. and Johnson, L., and Goebel, D., and Fitzgerald, D.}, title = {Effects of an Internally-Mounted Cathode on Hall Thruster Plume Properties}, booktitle = {42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit}, year = {2006}, series = {AIAA paper no. 2006-4482}, address = {Sacramento, CA}, month = {JUL}, organization = {AIAA/ASME/SAE/ASEE}, keywords = {Hall thruster, cathode, plasma plume, 1yr\_project}, owner = {erikg}, timestamp = {2008.10.17}, url = {http://www.aiaa.org/content.cfm?pageid=413} } @ARTICLE{hofer_internal_ht_cathode_2008, author = {Richard R. Hofer AND Lee K. Johnson AND Dan M. Goebel AND Richard E. Wirz}, title = {Effects of Internally-Mounted Cathodes on Hall Thruster Plume Properties}, journal = {(submitted for publication)}, year = {2008}, owner = {erikg}, timestamp = {2008.04.03} } @ARTICLE{hoffman_tem_2007, author = {M.~Hoffman and D.R.~Ernst}, title = {Linear and Nonlinear Studies of Trapped Electron Mode Turbulence}, journal = {Bulletin of the American Physical Society}, year = {2007}, volume = {52}, pages = {JP8.35}, number = {11}, month = {NOV}, keywords = {TEM}, owner = {erikg}, timestamp = {2009.07.22}, url = {http://meetings.aps.org/link/BAPS.2007.DPP.JP8.35} } @ARTICLE{hogan_core/divertor/wall_1997, author = {J. T. Hogan and R. Maingi and P. K. Mioduszewski and Th. Hutter and C. C. Klepper and M. R. Wade}, title = {Core/divertor/wall particle dynamics in the {DIII-D} tokamak}, journal = {Journal of Nuclear Materials}, year = {1997}, volume = {241-243}, pages = {612--617}, month = feb, abstract = {A wall model developed for the analysis of Tore Supra wall loading experiments has been applied to an experiment on {DIII-D} which demonstrated a substantial capacity for retention of deuterium gas in an all-graphite environment, and which showed the efficacy of the pumped divertor to deplete a gas-loaded wall. The Tore Supra model has been extended and applied to evaluate the particle exchange mechanisms between the core, divertor, and wall. Data-constrained plasma modeling is done for the discharges of the load/unload sequence. The poloidal distribution of the charge exchange flux profile to the divertor and outer wall is determined from the Eirene neutral transport code, to estimate the effective working areas for particle exchange and saturation. The deposition and saturation of the hydrogenic efflux in the {aC:H} layer and graphite is modeled with the {1-D} {WDIFFUSE} code, applied to the regions fuelled by charge exchange flux to predict the instantaneous local wall recycling coefficient. A mechanism is proposed to explain the previous paradoxical result that exhaust quickly ({\textasciitilde} 3 s) balances the only particle input, due to beam fueling, whereas a long term net wall depletion is observed over {\textasciitilde} 10 discharges. The saturation and depletion of wall layers fuelled by energetic charge exchange particles provides such a mechanism.}, doi = {{10.1016/S0022-3115(97)80109-2}}, issn = {0022-3115}, keywords = {Active pumping, {DIII-D,} Tokamak, Wall pumping}, url = {http://www.sciencedirect.com/science/article/B6TXN-47TVNGK-31/2/8f1d9ceb81a7fed7fbe7d58f88f03a82} } @ARTICLE{holland_validating_2008, author = {C. Holland and J. Candy and R. E. Waltz and A. E. White and G. R. {McKee} and M. W. Shafer and L. Schmitz and G. R. Tynan}, title = {Validating simulations of core tokamak turbulence: current status and future directions}, journal = {Journal of Physics: Conference Series}, year = {2008}, volume = {125}, pages = {012043}, abstract = {Validating predictive models of turbulent transport in magnetically confined plasmas requires comparisons of detailed fluctuation statistics, in addition to net energy flows. Using measurements from new and improved diagnostics on the {DIII-D} tokamak, we have performed a series of comparisons against predictions from the {GYRO} code. The development and application of synthetic diagnostics that model the spatial sensitivities of a given experimental fluctuation diagnostic is essential for these comparisons. At r/a = 0.56, we find very good agreement between the predicted and measured energy fluxes and fluctuation power spectra. At r/a = 0.8, however, the simulations underpredict the energy flows by a factor of seven and fluctuation amplitudes by a factor of 3 but successfully reproduce the shapes of the experimentally measured fluctuation power spectra. At both locations significant attenuation in the synthetic power spectra and fluctuation levels is observed relative to 'unfiltered' levels. Additional results contrasting local and nonlocal simulation results and convergence in toroidal mode number spacing are presented.}, issn = {1742-6596}, shorttitle = {Validating simulations of core tokamak turbulence}, url = {http://www.iop.org/EJ/abstract/1742-6596/125/1/012043/} } @ARTICLE{horton_toroidal_1981, author = {Jr. Horton and {Duk-In} Choi and W. M. Tang}, title = {Toroidal drift modes driven by ion pressure gradients}, journal = {Physics of Fluids}, year = {1981}, volume = {24}, pages = {1077--1085}, number = {6}, month = jun, doi = {10.1063/1.863486}, keywords = {{FLUCTUATIONS,} {ION} {TEMPERATURE,} {OSCILLATION} {MODES,} {PARAMETERIC} {INSTABILITIES,} {PLASMA} {DRIFT,} {PRESSURE} {GRADIENTS,} {SHEAR,} {THERMAL} {CONDUCTIVITY,} {TOROIDAL} {CONFIGURATION,} {TURBULENCE}}, url = {http://link.aip.org/link/?PFL/24/1077/1} } @ARTICLE{horton_drift_1999, author = {W. Horton}, title = {Drift waves and transport}, journal = {Reviews of Modern Physics}, year = {1999}, volume = {71}, pages = {735}, number = {3}, month = apr, note = {Copyright {(C)} 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {Drift waves occur universally in magnetized plasmas producing the dominant mechanism for the transport of particles, energy and momentum across magnetic field lines. A wealth of information obtained from quasistationary laboratory experiments for plasma confinement is reviewed for drift waves driven unstable by density gradients, temperature gradients and trapped particle effects. The modern understanding of Bohm transport and the role of sheared flows and magnetic shear in reducing the transport to the {gyro-Bohm} rate are explained and illustrated with large scale computer simulations. The types of mixed wave and vortex turbulence spontaneously generated in nonuniform plasmas are derived with reduced magnetized fluid descriptions. The types of theoretical descriptions reviewed include weak turbulence theory, Kolmogorov anisotropic spectral indices, and the mixing length. A number of standard turbulent diffusivity formulas are given for the various space-time scales of the drift-wave turbulent mixing.}, doi = {{10.1103/RevModPhys.71.735}}, url = {http://link.aps.org/abstract/RMP/v71/p735} } @BOOK{hortonhandbookplasmaphysics, title = {Handbook of Plasma Physics}, year = {1984}, author = {W. Horton}, volume = {2}, keywords = {GPP2, quasilinear theory}, owner = {erikg}, timestamp = {2007.05.09} } @ARTICLE{hosea_lhcd_2005, author = {J. Hosea and D. Beals and W. Beck and S. Bernabei and W. Burke and R. Childs and R. Ellis and E. Fredd and N. Greenough and M. Grimes and D. Gwinn and J. Irby and S. Jurczynski and P. Koert and C.C. Kung and G.D. Loesser and E. Marmar and R. Parker and J. Rushinski and G. Schilling and D. Terry and R. Vieira and J.R. Wilson and J. Zaks}, title = {The LHCD launcher for Alcator C-Mod--Design, construction, calibration and testing}, journal = {Fusion Engineering and Design}, year = {2005}, volume = {74}, pages = {479-483}, abstract = {MIT and PPPL have joined together to fabricate a high-power lower hybrid current drive (LHCD) system for supporting steady-state AT regime research on Alcator C-Mod. The goal of the first step of this project is to provide 1.5 MW of 4.6 GHz rf power to the plasma with a compact launcher which has excellent spectral selectivity and fits into a single C-Mod port. Some of the important design, construction, calibration and testing considerations for the launcher leading up to its installation on C-Mod are presented here.}, keywords = {C-Mod,Launcher,Lower hybrid current drive (LHCD)}, url = {http://www.sciencedirect.com/science/article/B6V3C-4H68V5G-1/2/2ff9a2ec86cf892f383c3844a41e7d58} } @ARTICLE{huang_unfolding_2008, author = {T. X. Huang and Y. K. Ding and Z. J. Zheng and W. Y. Miao and Z. R. Cao and S. E. Jiang and S. Y. Liu and Z. L. Liu}, title = {Unfolding core asymmetries with x-ray emission images in symmetry diagnostic experiments}, journal = {Review of Scientific Instruments}, year = {2008}, volume = {79}, pages = {053503}, number = {5}, doi = {10.1063/1.2924212}, issn = {00346748}, url = {http://link.aip.org/link/RSINAK/v79/i5/p053503/s1&Agg=doi} } @ARTICLE{hussein_collisionless_1990, author = {Makarem A. Hussein and G. A. Emmert}, title = {Collisionless plasma presheath in a nonuniform magnetic field}, journal = {Physics of Fluids B: Plasma Physics}, year = {1990}, volume = {2}, pages = {218-221}, doi = {10.1063/1.859531}, keywords = {BOLTZMANN STATISTICS,BOLTZMANNVLASOV EQUATION,COLLISIONLESS PLASMA,CORRELATIONS,DYNAMICS,ELECTRONS,IONS,ITERATIVE METHODS,MAGNETIC FIELDS,MONTE CARLO METHOD,NUMERICAL SOLUTION,PLASMA DRIFT,PLASMA SHEATH,SIMULATION,WALLS}, url = {http://link.aip.org/link/?PFB/2/218/1} } @BOOK{hutchinson_principles_2002, title = {Principles of plasma diagnostics}, publisher = {Cambridge University Press}, year = {2002}, author = {I.H. Hutchinson}, address = {New York}, edition = {Second}, keywords = {diagnostics}, url = {http://catalog.princeton.edu/cgi-bin/Pwebrecon.cgi?v1=1\&ti=1,1\&SAB1=Hutchinson\&BOOL1=all\%20of\%20these\&FLD1=Author\%20\%28NAMP\%29\&GRP1=AND\%20with\%20next\%20set\&SAB2=diagnostics\%2A\&BOOL2=all\%20of\%20these\&FLD2=Title\%20\%28TITP\%29\&GRP2=AND\%20with\%20next\%20set\&SAB3=\&BOOL3=all\%20of\%20these\&FLD3=Keyword\%20Anywhere\%20\%28GKEY\%29\&CNT=50\&PID=q@oGsHoIu@oGox\%3EJnxNIt@oGo\%3C\%3C\%3C\&SEQ=20070131093121\&SID=6} } @ARTICLE{kaganovich07, author = {{I. D. Kaganovich} and {Y. Raitses} and {D. Sydorenko} and {A. Smolyakov}}, title = {Kinetic effects in a Hall thruster discharge}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {057104}, number = {5}, month = may, abstract = {Recent analytical studies and particle-in-cell simulations suggested that the electron velocity distribution function in EB discharge of annular geometry Hall thrusters is non-Maxwellian and anisotropic. The average kinetic energy of electron motion in the direction parallel to the thruster channel walls (across the magnetic field) is several times larger than that in the direction normal to the walls. Electrons are stratified into several groups depending on their origin (e.g., plasma or channel walls) and confinement (e.g., lost on the walls or trapped in the plasma). Practical analytical formulas are derived for the plasma flux to the wall, secondary electron fluxes, plasma potential, and electron cross-field conductivity. Calculations based on these formulas fairly agree with the results of numerical simulations. The self-consistent analysis demonstrates that the elastic electron scattering in collisions with atoms and ions plays a key role in formation of the electron velocity distribution function and the plasma potential with respect to the walls. It is shown that the secondary electron emission from the walls may significantly enhance the electron conductivity across the magnetic field but only weakly affects the insulating properties of the near-wall sheath. Such self-consistent decoupling between the secondary electron emission effects on the electron energy losses and the electron cross-field transport is currently not captured by the existing fluid and hybrid models of Hall thrusters.}, doi = {10.1063/1.2709865}, keywords = {hall thrusters, 1yr_project}, owner = {egranste}, timestamp = {2007.05.07} } @ARTICLE{igami_searching_2006, author = {H. Igami and S. Kubo and H. P. Laqua and K. Nagasaki and S. Inagaki and T. Notake and T. Shimozuma and Y. Yoshimura and T. Mutoh and LHD Experimental Group}, title = {Searching for O-X-B mode-conversion window with monitoring of stray microwave radiation in LHD}, journal = {Rev. Sci. Instrum.}, year = {2006}, volume = {77}, pages = {10E931--3}, month = oct, doi = {10.1063/1.2336460}, keywords = {antennas in plasma,plasma Bernstein waves,plasma diagnostics,plasma electromagnetic wave propagation,plasma radiofrequency heating,plasma temperature,plasma toroidal confinement,stellarators}, url = {http://link.aip.org/link/?RSI/77/10E931/1} } @ARTICLE{intrator_virtual_1988, author = {T. Intrator and M. H. Cho and E. Y. Wang and N. Hershkowitz and D. Diebold and J. DeKock}, title = {The virtual cathode as a transient double sheath}, journal = {Journal of Applied Physics}, year = {1988}, volume = {64}, pages = {2927-2933}, note = {I: stationary potential wells (in time and space) require ion pumping to remove trapped ions, ex. along the third dimension of a potential dip. This paper describes the transient (60 Hz) space-charge double sheath. II: collisionless plasma, $P\sim 7 10^{-5}-10^{-3}, \quad Te \sim 1-1.5 eV, \quad Ti \sim 0.3 eV,\quad Tcath \sim 1300K$ Cathode is floating; flux balance dominated by the attenuated curents from the cathode (by virtual cathode) and plasma (by sheath). IV: Debye length $\sim$0.1 cm for cathode electrons to $\sim$0.9 cm for plasma thermal electrons. Large potential dip located 0.5-1cm (several $\lambda_{Dc}$) from the cathode. For Richardson-Dushmann formula, use $A=3.0 A cm^{-2}K^{-2}$ and $\phi_w$ = 2.63 eV. Increasing emission parameter ($\delta$ = max thermionic cathode current/thermal electron collection current to plasma) corresponds to increasing cathode temperature. Virtual cathode exists for $\delta > 1.2$; for high enough emission, a double layer occurs when a streaming ion population is present far from the cathode. V. Charge exchange time is calculated to be about $300\mu s$, which is much shorter than the coulomb scattering time. CX preferentially produces slow ions, becausethe scattering rate scales with ion velocity, and all resulting ions have the low energies of the neutral population. Electron-rich virtual cathode evolves in time to a QN plasma as it fills with slow ions. CX rate is proportional to the density, and increases over an order of mag. as the neutral pressure is increased. At $78 \mu$ torr, the potential mininum is initially ~2V below the cathode voltage. The mfp for CX is the same order of magnitude as the size of the potential structure, so the fact that slow ions from CX destroy the potential dip makes sense. Conclusion is that the idealized model of non-monotonic potentials is only valid while the effects of particle sources and sinks are not significant. VI: ions can be pumped out by following a monotonic decreasing potential to a plasma boundary (glass) VII: Don't understand why they say "virtual cathode... self-consistent only for a transient ... system if there is significant neutral density." Doesn't decreased neutral density lengthen the lifetime of the virtual cathode in the absence of ion pumping? Potential structures extend for many Debye lengths, and potential dips much larger than the cathode potential were observed. Secondary electron emission can generate similar effects. App: sheath potential is the potential at the point in the virtual cathode-sheath structure where $n_e=n_i$.}, keywords = {CATHODES,ELECTRIC POTENTIAL,PLASMA DIAGNOSTICS,PLASMA SHEATH}, url = {http://link.aip.org/link/?JAP/64/2927/1} } @ARTICLE{intrator_multiple_1993, author = {T. Intrator and J. Menard and N. Hershkowitz}, title = {Multiple magnetized double layers in the laboratory}, journal = {Physics of Fluids B: Plasma Physics}, year = {1993}, volume = {5}, pages = {806-811}, month = mar, url = {http://link.aip.org/link/?PFB/5/806/1} } @ARTICLE{ito_low-power_2006, author = {Tsuyohito Ito and Mark A. Cappelli}, title = {Low-power magnetized microdischarge ion source}, journal = {Applied Physics Letters}, year = {2006}, volume = {89}, pages = {061501-3}, doi = {10.1063/1.2335612}, keywords = {discharges (electric),ionisation,plasma collision processes,plasma sources,plasma transport processes}, url = {http://link.aip.org/link/?APL/89/061501/1} } @ARTICLE{itoh_physics_2006, author = {K. Itoh and S.-I. Itoh and P. H. Diamond and T. S. Hahm and A. Fujisawa and G. R. Tynan and M. Yagi and Y. Nagashima}, title = {Physics of zonal flows}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {055502-11}, month = may, note = {References 1 and 2 are more ``full-length'' review articles. ZFs are $n=0$,$m=0$ electric field (potential) fluctuations with finite radial wavenumber, so since $\bar{E}=E_r\hat{r}$, they cannot drive radial transport via ExB drift; also, they cannot get energy from typical free energy sources due to radial gradients. They mitigate transport by shearing the drift waves, hence quenching and extracting energy from them. Why are these modes important as regulators of DW turbulence relative to other low-n modes? \begin{enumerate} \item with n=0 and kparallel = 0, they aren't screened by Boltzman electrons, so in their dispersion relation, they have minimal inertia which results in large flow velocities when driven by DWs, unless damping limits this. Zonal flows aren't as effective in drawing energy from the ETG mode, because both zonal flows and the ETG mode excite a Boltzman ion response (ie. they have comparable inertia to other modes). \item Modes of minimal Landau damping, so the only linear dissipation is due to collisions \item With n=0, they are incapable of driving ExB radial diffusion and are a ``benign repository'' for free energy \end{enumerate} Ref. 1 has a more thorough explanation of the instability, the pictorial argument is a bit hard to follow. If the frequency of the ZF $\Omega \ll \omega_k$ where $\omega_k$ is the freq. of the DW, then if the DW is perturbed slightly, $k_r$ will random walk in the shear layers, increasing $\langle k_r^2 \rangle$. Since $\omega_k = \omega_{e\asterisk}/(1+k_\perp^2\rho_s^2)$ the DW freq. decreases and since $\Omega \ll \omega_k$, the wave action density is conserved and the DW wave energy increases; ie. the DW transfered energy to the ZF since the total energy of the two is constant.}, keywords = {plasma drift waves,plasma flow,plasma transport processes,plasma turbulence,reviews,shear flow}, url = {http://link.aip.org/link/?PHP/13/055502/1} } @ARTICLE{itoh_bicoherence_2005, author = {K. Itoh and Y. Nagashima and {S.-I.} Itoh and P. H. Diamond and A. Fujisawa and M. Yagi and A. Fukuyama}, title = {On the bicoherence analysis of plasma turbulence}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {102301--9}, number = {10}, month = oct, note = {Paper referenced by Dave Smith to use the {NSTX} high-k scattering diagnostic to calculate mode-coupling coefficients for turbulence.}, doi = {10.1063/1.2062627}, keywords = {plasma drift waves,plasma flow,plasma fluctuations,plasma nonlinear processes,plasma turbulence}, url = {http://link.aip.org/link/?PHP/12/102301/1} } @ARTICLE{iwase_laser-produced_1998, author = {O. Iwase and W. Suss and D. H. H. Hoffmann and M. Roth and C. Stockl and M. Geissel and W. Seelig and R. Bock}, title = {{Laser-Produced} Plasma Diagnostics by a Combination of Schlieren Method and {Mach-Zehnder} Interferometry}, journal = {Physica Scripta}, year = {1998}, volume = {58}, pages = {634--635}, number = {6}, abstract = {An optical method for laser-produced plasma diagnostics, for which a crucial study is a shock-wave phenomena, is newly suggested as a combination of the well-known Schlieren method to study shock-wave phenomena and {Mach-Zehnder} interferometry for evaluating the electron density.}, issn = {0031-8949}, url = {http://www.iop.org/EJ/abstract/1402-4896/58/6/017} } @BOOK{jackson_electrodynamics, title = {Classical Electrodynamics}, publisher = {Wiley}, year = {1999}, author = {John David Jackson}, pages = {808}, address = {New York}, edition = {3rd ed}, isbn = {{047130932X}}, keywords = {Electrodynamics}, lccn = {{QC631} {.J3} 1999}, url = {http://catalog.princeton.edu/cgi-bin/Pwebrecon.cgi?v1=1&ti=1,1&SAB1=Jackson&BOOL1=all%20of%20these&FLD1=Author%20(NAMP)&GRP1=AND%20with%20next%20set&SAB2=electrodynamics&BOOL2=all%20of%20these&FLD2=Title%20(TITP)&GRP2=AND%20with%20next%20set&SAB3=&BOOL3=all%20of%20these&FLD3=Keyword%20Anywhere%20(GKEY)&CNT=50&PID=3qelAkw8btQAK-C9cL1ObSh67X5&SEQ=20090729124903&SID=1} } @ARTICLE{janeslowder, author = {Janes, G.~S. and Lowder, R.~S.}, title = {Anomalous Electron Diffusion and Ion Acceleration in a Low-Density Plasma}, journal = {Physics of Fluids}, year = {1966}, volume = {9}, pages = {1115-1123}, number = {6}, keywords = {hall thruster, anomalous cross field transport, 1yr_project}, owner = {egranste}, timestamp = {2007.05.16} } @ARTICLE{jardin_m3d-c1_2008, author = {S. C. Jardin and N. Ferraro and X. Luo and J. Chen and J. Breslau and K. E. Jansen and M. S. Shephard}, title = {The {M3D-C1} approach to simulating {3D} 2-fluid magnetohydrodynamics in magnetic fusion experiments}, journal = {Journal of Physics: Conference Series}, year = {2008}, volume = {125}, pages = {012044}, abstract = {A new approach for solving the {3D} {MHD} equations in a strongly magnetized toroidal plasma is presented which uses high-order {2D} finite elements with C1 continuity. The vector fields use a physics-based decomposition. An efficient implicit time advance separates the velocity and field advance. {ITAPS} {(SCOREC)} adaptivity software and {TOPS} solvers are used.}, issn = {1742-6596}, url = {http://www.iop.org/EJ/abstract/1742-6596/125/1/012044} } @ARTICLE{jardin_high-order_2007, author = {{S.C.} Jardin and J. Breslau and N. Ferraro}, title = {A high-order implicit finite element method for integrating the two-fluid magnetohydrodynamic equations in two dimensions}, journal = {Journal of Computational Physics}, year = {2007}, volume = {226}, pages = {2146--2174}, number = {2}, month = oct, abstract = {We describe a new method for solving the time-dependent two-fluid magnetohydrodynamic {(2F-MHD)} equations in two dimensions that has significant advantages over other methods. The stream-function/potential representation of the velocity and magnetic field vectors, while fully general, allows accurate description of nearly incompressible fluid motions and manifestly satisfies the divergence condition on the magnetic field. Through analytic manipulation, the split semi-implicit method breaks the full matrix time advance into four sequential time advances, each involving smaller matrices. The use of a high-order triangular element with continuous first derivatives {(C1} continuity) allows the Galerkin method to be applied without introduction of new auxiliary variables (such as the vorticity or the current density). These features, along with the manifestly compact nature of the fully node-based C1 finite elements, lead to minimum size matrices for an unconditionally stable method with order of accuracy h4. The resulting matrices are compatible with direct factorization using {SuperLU\_dist.} We demonstrate the accuracy of the method by presenting examples of two-fluid linear wave propagation, two-fluid linear eigenmodes of a tilting cylinder, and of a challenging nonlinear problem in two-fluid magnetic reconnection.}, doi = {10.1016/j.jcp.2007.07.003}, issn = {0021-9991}, url = {http://www.sciencedirect.com/science/article/B6WHY-4P8GX5C-1/2/6df884945ea52d0b8c825874334dee44} } @ARTICLE{jenkins_review_1969, author = {RO JENKINS}, title = {A Review of Thermoionic Cathodes}, journal = {VACUUM}, year = {1969}, volume = {19}, pages = {353-359}, issn = {0042-207X}, keywords = {cathode,thermionic emission, 1yr_project} } @ARTICLE{jenkinstrodden, author = {Jenkins, R.~O., and Trodden, W.~G.}, title = {Evaporation of thorium from carburized thoriated tungsten cathodes}, journal = {Brittish Journal of Applied Physics}, year = {1959}, volume = {10}, pages = {10-15}, keywords = {tungsten, cathode, 1yr_project}, owner = {egranste}, timestamp = {2007.05.21}, url = {http://www.google.com/url?sa=t&ct=res&cd=10&url=http%3A%2F%2Fwww.iop.org%2FEJ%2Farticle%2F0508-3443%2F10%2F1%2F303%2Fbjv10i1p10.pdf&ei=LeJRRtzaAoH6wQK7ycWJDQ&usg=AFrqEzfQGHOtQE-3BlPQGUW52cQvRANo3A&sig2=9-P1GapIL_uzRmWxFNtD9w} } @INBOOK{jenko_etg_chapter_2002, chapter = {Simulation and theory of electron temperature gradient turbulence}, title = {Theory of Fusion Plasmas}, publisher = {Societa italiana di fisica}, year = {2002}, editor = {J.W. Connor and O. Sauter and E. Sindoni}, author = {F. Jenko and W. Dorland and A. Kendl and D. Strintzi}, address = {Bologna}, owner = {erikg}, timestamp = {2009.05.08}, url = {http://catalog.princeton.edu/cgi-bin/Pwebrecon.cgi?SC=Author&SA=Joint%20Varenna-Lausanne%20International%20Workshop%20on&PID=fEu8-H4TauTcBrxmIolsx96nB&BROWSE=3&HC=1&SID=2} } @ARTICLE{jiang_interferometric_1999, author = {Y. Jiang and D. L. Brower and N. E. Lanier}, title = {Interferometric measurement of high-frequency density fluctuations in Madison symmetric torus}, journal = {Proceedings of the 12th topical conference on high temperature plasma diagnostics}, year = {1999}, volume = {70}, pages = {703--706}, doi = {10.1063/1.1149275}, keywords = {CO2, electron density, light interferometry, phase measurement, plasma diagnostics, plasma turbulence, reversed field pinch}, url = {http://link.aip.org/link/?RSI/70/703/1} } @ARTICLE{jones_controlled_2003, author = {B. Jones and P. C. Efthimion and G. Taylor and T. Munsat and J. R. Wilson and J. C. Hosea and R. Kaita and R. Majeski and R. Maingi and S. Shiraiwa and J. Spaleta and A. K. Ram}, title = {Controlled Optimization of Mode Conversion from Electron Bernstein Waves to Extraordinary Mode in Magnetized Plasma}, journal = {Physical Review Letters}, year = {2003}, volume = {90}, pages = {165001}, number = {16}, month = apr, note = {Copyright {(C)} 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {In the {CDX-U} spherical torus, agreement between radiation temperature and Thomson scattering electron temperature profiles indicates ∼100\% conversion of thermally emitted electron Bernstein waves to the X mode. This has been achieved by controlling the electron density scale length {(Ln)} in the conversion region with a local limiter outside the last closed flux surface, shortening Ln to the theoretically required value for optimal conversion. From symmetry of the conversion process, prospects for efficient coupling in heating and current drive scenarios are strongly supported.}, doi = {{10.1103/PhysRevLett.90.165001}}, url = {http://link.aps.org/abstract/PRL/v90/e165001} } @PHDTHESIS{jones_electron_2002, author = {Brent Manley Jones}, title = {Electron Bernstein wave thermal emission and mode conversion in the {CDX-U} spherical torus}, school = {Princeton University}, year = {2002}, note = {{Ph.D.}}, abstract = {In tokamaks (toroidal magnetically confined fusion plasmas), electron cyclotron emission has been used for many years to measure the electron temperature ( T e ) profile. A microwave radiometer detects blackbody emission, with a given frequency corresponding to a unique electron cyclotron harmonic ( n f ce ) resonance layer within the plasma. Alternately, electromagnetic waves can be launched to heat or drive current at cyclotron resonances. These techniques cannot be used in a class of "overdense" plasmas in which the plasma frequency ( f pe ) is much greater than f ce so that electromagnetic waves in this frequency range are evanescent. An alternate wave is considered here which enables similar techniques in overdense spherical tokamaks {(ST)} and other high-² plasmas. The electrostatic electron Bernstein wave {(EBW)} is thermally emitted at n f ce resonances, and can propagate below f pe . The {EBW} can mode convert to electromagnetic waves at the upper-hybrid resonance {(UHR)} layer surrounding the plasma, at which point it can be detected using standard radiometric techniques. In this work, {EBW} mode conversion to X-mode waves {(B-X)} is studied as a means to measure T e in an overdense plasma. An in-vacuum antenna measures {B-X} emission in the {CDX-U} {ST.} To control and optimize the {B-X} conversion, a local limiter shortens the density scale length ( L n ) measured with a Langmuir probe array at the {UHR,} which theoretically allows the mode conversion efficiency ( C ) to approach unity. The emission is predominantly X-mode polarized and emitted near the n f ce layer. Comparing the T e profile measured by Thomson scattering to the {EBW} radiation temperature ( T rad ) profile verifies C ∼ 100\%. Large (∼50\%) fluctuations in T rad are observed, though, and T rad ∼ T e is seen only at the peak of fluctuating emission. Theoretical C calculated with measured, fluctuating L n is ∼75\% correlated with T rad . Other sources of T rad variation are discussed. These results provide experimental evidence supporting {B-X} conversion theory and have demonstrated the feasibility of measuring T e through {B-X} emission. Since the inverse {X-B} conversion process obeys the same physics, this work also validates the prospect of performing heating/current drive in an {ST} via mode conversion of launched X-mode waves to the {EBW.}}, keywords = {{Electromagnetism,Fluid} {dynamics,Gases}}, url = {http://proquest.umi.com/pqdweb?did=764773541&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @PHDTHESIS{jones_low-aspect-ratio_1995, author = {Theodore George Jones}, title = {Low-aspect-ratio tokamak start-up and operational current limits in {CDX-U}}, school = {Princeton University}, year = {1995}, note = {{Ph.D.}}, comment = {A new, small, low-aspect-ratio tokamak {(LART),} named the Current Drive {Experiment-Upgrade} {(CDX-U),} has been designed and built for the investigation and development of the {LART} configuration, as well as for the investigation of novel current drive methods. Recently, an inductive ohmic heating and current drive {(OH)} system, including a compact high-field {OH} transformer coil, was designed and installed in {CDX-U,} enabling the study of {LART} plasmas with higher plasma currents and temperatures. Electron cyclotron resonance heating {(ECH)} was used in {CDX-U} to assist plasma breakdown, allowing breakdown with low initial induced voltage. Plasma start-up was achieved with transmitted {ECH} power of approximately l\% of the maximum coupled {OH} power, at loop voltages as low as 1 Volt, and in toroidal magnetic fields ranging by a factor of 2.5 in strength. The reduction in loop voltage necessary for start-up minimized large, induced eddy currents in the toroidally continuous vessel walls common to {LARTs.} Plasma start-up and control in the presence of these significant vessel eddy currents was demonstrated, an important achievement for {LART} operation. Calculated ohmic efficiency, in terms of the Ejima coefficient. {\$C{\textbackslash}sb{E}\$,} compared favorably with that found in other tokamaks, yielding {\$C{\textbackslash}sb{E}} {\textbackslash}geq\$ 0.3-0.4. An operational current limit was found during extensive {CDX-U} ohmic operation, corresponding to an {MHD} safety factor, q(a), of approximately 3.5, a new low demonstrated q-limit for an aspect ratio, A, of 1.6. Studies of magnetic fluctuations in a range of plasma current from 15 {kA} to 40 {kA} revealed a coherent, saturating, 10-15 {kHz} frequency mode, with a toroidal mode number of n = l and a poloidol mode number ranging from m = 1 to m = 3. Numerical stability analysis of a magnetic reconstruction of a typical discharge exhibiting this mode indicated ideal stability. Previous studies of this mode at the lower plasma currents showed the amplitude increasing dramatically as the safety factor approached the operational current limit of q(a) = 3.5, and a radial mode structure consistent with magnetic island formation. These n = 1, low m, resistive modes are a good candidate for an {MHD} instability causing the observed operational current limit.}, keywords = {{Electromagnetism,Fluid} {dynamics,Gases}}, url = {http://proquest.umi.com/pqdweb?did=741102591&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @INBOOK{kadomtsev_reviews_turbulence_1970, chapter = {Turbulence in Toroidal Systems}, pages = {249--400}, title = {Reviews of Plasma Physics}, publisher = {Consultants Bureau}, year = {1970}, editor = {M.A.~Leontovich}, author = {B.B.~Kadomtsev and O.P~Pogutse}, volume = {5}, comment = {furth circulation desk QC718 .V63}, keywords = {GPP2, ITG, Ion Temperature Gradient instability, trapped particle instabilities, trapped electron mode, ETG, electron temperature gradient instability, drift waves}, owner = {erikg}, timestamp = {2009.07.22} } @ARTICLE{2000PhRvE..61.1875K, author = {{Kaganovich}, I. and {Mi{\v s}ina}, M. and {Berezhnoi}, S.~V. and {Gijbels}, R.}, title = {{Electron Boltzmann kinetic equation averaged over fast electron bouncing and pitch-angle scattering for fast modeling of electron cyclotron resonance discharge}}, journal = {\pre}, year = {2000}, volume = {61}, pages = {1875-1889}, month = feb, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2000PhRvE..61.1875K}, doi = {10.1103/PhysRevE.61.1875}, keywords = {ECR discharge, mirrors, open systems, 2yr_project} } @ARTICLE{2002PhPl....9.4788K, author = {{Kaganovich}, I.~D.}, title = {{How to patch active plasma and collisionless sheath: A practical guide}}, journal = {Physics of Plasmas}, year = {2002}, volume = {9}, pages = {4788-4793}, month = nov, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2002PhPl....9.4788K}, doi = {10.1063/1.1515274}, eprint = {arXiv:physics/0208041}, keywords = {sheath, 2yr_project} } @ARTICLE{kaita_spherical_2002, author = {R. Kaita and R. Majeski and M. Boaz and P. Efthimion and B. Jones and D. Hoffman and H. Kugel and J. Menard and T. Munsat and A. {Post-Zwicker} and V. Soukhanovskii and J. Spaleta and G. Taylor and J. Timberlake and R. Woolley and L. Zakharov and M. Finkenthal and D. Stutman and G. Antar and R. Doerner and S. Luckhardt and R. Maingi and M. Maiorano and S. Smith}, title = {Spherical torus plasma interactions with large-area liquid lithium surfaces in {CDX-U}}, journal = {Fusion Engineering and Design}, year = {2002}, volume = {61-62}, pages = {217--222}, month = nov, abstract = {The current drive experiment-upgrade {(CDX-U)} device at the Princeton Plasma Physics Laboratory {(PPPL)} is a spherical torus {(ST)} dedicated to the exploration of liquid lithium as a potential solution to reactor first-wall problems such as heat load and erosion, neutron damage and activation, and tritium inventory and breeding. Initial lithium limiter experiments were conducted with a toroidally-local liquid lithium rail limiter {(L3)} from the University of California at San Diego {(UCSD).} Spectroscopic measurements showed a clear reduction of impurities in plasmas with the L3, compared to discharges with a boron carbide limiter. The evidence for a reduction in recycling was less apparent, however. This may be attributable to the relatively small area in contact with the plasma, and the presence of high-recycling surfaces elsewhere in the vacuum chamber. This conclusion was tested in subsequent experiments with a fully toroidal lithium limiter that was installed above the floor of the vacuum vessel. The new limiter covered over ten times the area of the L3 facing the plasma. Experiments with the toroidal lithium limiter have recently begun. This paper describes the conditioning required to prepare the lithium surface for plasma operations, and effect of the toroidal liquid lithium limiter on discharge performance.}, doi = {10.1016/S0920-3796(02)00117-5}, issn = {0920-3796}, keywords = {Lithium {limiter,Plasma-surface} {interactions,Spherical} torus}, url = {http://www.sciencedirect.com/science/article/B6V3C-46Y5D93-C/2/7ef52a8e903c8151e801dbc2895c73d1} } @ARTICLE{kaita_extremely_2007, author = {R. Kaita and R. Majeski and R. Doerner and T. Gray and H. Kugel and T. Lynch and R. Maingi and D. Mansfield and V. Soukhanovskii and J. Spaleta and J. Timberlake and L. Zakharov}, title = {Extremely low recycling and high power density handling in {CDX-U} lithium experiments}, journal = {Journal of Nuclear Materials}, year = {2007}, volume = {363-365}, pages = {1231--1235}, month = jun, abstract = {The mission of the Current Drive {eXperiment-Upgrade} {(CDX-U)} spherical tokamak is to investigate lithium as a plasma-facing component {(PFC).} The latest {CDX-U} experiments used a combination of a toroidal liquid lithium limiter and lithium wall coatings applied between plasma shots. Recycling coefficients for these plasmas were deduced to be 30\% or below, and are the lowest ever observed in magnetically-confined plasmas. The corresponding energy confinement times showed nearly a factor of six improvement over discharges without lithium {PFC's.} An electron beam (e-beam) for evaporating lithium from the toroidal limiter was one of the techniques used to create lithium wall coatings in {CDX-U.} The evaporation was not localized to the e-beam spot, but occurred only after the entire volume of lithium in toroidal limiter was liquefied. This demonstration of the ability of lithium to handle high heat loads can have significant consequences for {PFC's} in future burning plasma devices.}, doi = {10.1016/j.jnucmat.2007.01.229}, issn = {0022-3115}, keywords = {{cdx-u,Liquid} {metal,Lithium,Particle} {control,Recycling,Wall} pumping}, url = {http://www.sciencedirect.com/science/article/B6TXN-4N146FD-8/2/6aa528b080bff0efbbfc5de6893f133a} } @ARTICLE{kaita2007, author = {R. Kaita and R. Majeski and T. Gray and H. Kugel and D. Mansfield and J. Spaleta and J. Timberlake and L. Zakharov and R. Doerner and T. Lynch and R. Maingi and V. Soukhanovskii}, title = {Low recycling and high power density handling physics in the Current Drive Experiment-Upgrade with lithium plasma-facing components}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {056111}, number = {5}, eid = {056111}, note = {Lithium dissipated an electron beam of 1.5kW ($\textrm{60 MW/m^2}$) (due to generated convective flows). Need to understand liquid MHD effects. Li chosen for Tritium breeding, because it's the least reactive of the alkali metals, and it binds H well. E-beam was guided by vertical and TF coils to the tray, and its width (about 3 mm) determined from the current drawn by a probe as it was scanned across. Convection is thought to be driven by $j \cross B$ from the e-beam current and vertical field, as well as the Marangoni effect: related to the dependence of surface tension on temp, resulting in a fluid velocity of 10 m/s to transfer heat out of the region. Standard gas injectors and supersonic gas injector (with laval nozzle located within 1 cm above the last closed flux surf.) are used. Microwave interferometer used to measure line-averaged density. Impurity level (measured by filterscopes) of oxygen and carbon were significantly reduced. For high-confinement in a low-recycling regime, cannot have external particle source (from the edge) that causes edge mixing. In this ``D-region'', ambipolarity dictates that the best confined species determines the energy losses. Measurements show that temp. gradients are steeper, implying less collisionality in the scrape-off region. Also, liquid Li limiter discharges were stable against MHD modes (incl. resistive MHD modes which occured before) and safety factor $q \gt 1$. This is surprising, and an attempt at an explanation is given in p.7: unclear whether it is due to flattened temp. profile or because the hotter plasmas are less resistive and have a longer current penetration time.}, doi = {10.1063/1.2718509}, keywords = {Tokamak devices; plasma toroidal confinement; plasma-wall interactions; plasma transport processes; electron beams; plasma-beam interactions; fusion reactor design; fusion reactor materials}, numpages = {8}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/14/056111/1} } @ARTICLE{kalal_abel_1988, author = {Milan Kalal and Keith A. Nugent}, title = {Abel inversion using fast Fourier transforms}, journal = {Applied Optics}, year = {1988}, volume = {27}, pages = {1956--1959}, number = {10}, month = may, abstract = {A fast Fourier transform based Abel inversion technique is proposed. The method is faster than previously used techniques, potentially very accurate (even for a relatively small number of points), and capable of handling large data sets. The technique is discussed in the context of its use with {2-D} digital interferogram analysis algorithms. Several examples are given.}, doi = {{10.1364/AO.27.001956}}, url = {http://ao.osa.org/abstract.cfm?URI=ao-27-10-1956} } @ARTICLE{kammerer_exceptional_2008, author = {M. Kammerer and F. Merz and F. Jenko}, title = {Exceptional points in linear gyrokinetics}, journal = {Physics of Plasmas}, year = {2008}, volume = {15}, pages = {052102--7}, number = {5}, month = may, doi = {10.1063/1.2909618}, keywords = {plasma instability,plasma kinetic theory,plasma simulation}, url = {http://link.aip.org/link/?PHP/15/052102/1} } @ARTICLE{katanuma_collision_2003, author = {I. Katanuma and Y. Tatematsu and K. Ishii and T. Saito and K. Yatsu}, title = {Collision effects on the saturated electrostatic potential along a magnetic field line}, journal = {Physics of Plasmas}, year = {2003}, volume = {10}, pages = {677-682}, month = mar, doi = {10.1063/1.1544536}, keywords = {fusion reactor theory,magnetic mirrors,Monte Carlo methods,plasma collision processes,plasma magnetohydrodynamics,plasma simulation,plasma transport processes}, url = {http://link.aip.org/link/?PHP/10/677/1} } @ARTICLE{katsouleas_plasma_2006, author = {T. Katsouleas}, title = {Plasma accelerators race to 10 GeV and beyond}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {055503-7}, month = may, keywords = {electron beams,particle beam dynamics,plasma accelerators,plasma-beam interactions,plasma jets,plasma light propagation,reviews}, url = {http://link.aip.org/link/?PHP/13/055503/1} } @ARTICLE{kaye_confinement_2007, author = {S.M. Kaye and F.M. Levinton and D. Stutman and K. Tritz and H. Yuh and M.G. Bell and R.E. Bell and C.W. Domier and D. Gates and W. Horton and J. Kim and B.P. LeBlanc and N.C. Luhmann Jr and R. Maingi and E. Mazzucato and J.E. Menard and D. Mikkelsen and D. Mueller and H. Park and G. Rewoldt and S.A. Sabbagh and D.R. Smith and W. Wang}, title = {Confinement and local transport in the National Spherical Torus Experiment (NSTX)}, journal = {Nuclear Fusion}, year = {2007}, volume = {47}, pages = {499-509}, abstract = {The NSTX operates at low aspect ratio (R/a [?] 1.3) and high beta (up to 40\%), allowing tests of global confinement and local transport properties that have been established from higher aspect ratio devices. The NSTX plasmas are heated by up to 7 MW of deuterium neutral beams with preferential electron heating as expected for ITER. Confinement scaling studies indicate a strong BT dependence, with a current dependence that is weaker than that observed at higher aspect ratio. Dimensionless scaling experiments indicate a strong increase in confinement with decreasing collisionality and a weak degradation with beta. The increase in confinement with BT is due to reduced transport in the electron channel, while the improvement with plasma current is due to reduced transport in the ion channel related to the decrease in the neoclassical transport level. Improved electron confinement has been observed in plasmas with strong reversed magnetic shear, showing the existence of an electron internal transport barrier (eITB). The development of the eITB may be associated with a reduction in the growth of microtearing modes in the plasma core. Perturbative studies show that while L-mode plasmas with reversed magnetic shear and an eITB exhibit slow changes in \{\\rm L\}\{\_\{T\_\{\\rme\}\}\} across the profile after the pellet injection, H-mode plasmas with a monotonic q-profile and no eITB show no change in this parameter after pellet injection, indicating the existence of a critical gradient that may be related to the q-profile. Both linear and non-linear simulations indicate the potential importance of electron temperature gradient (ETG) modes at the lowest BT. Localized measurements of high-k fluctuations exhibit a sharp decrease in signal amplitude levels across the L-H transition, associated with a decrease in both ion and electron transport, and a decrease in calculated linear microinstability growth rates across a wide k-range, from the ion temperature gradient/TEM regime up to the ETG regime.}, doi = { 10.1088/0029-5515/47/7/001}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/47/7/001} } @ARTICLE{kaye_scaling_2007, author = {S. M. Kaye and R. E. Bell and D. Gates and B. P. {LeBlanc} and F. M. Levinton and J. E. Menard and D. Mueller and G. Rewoldt and S. A. Sabbagh and W. Wang and H. Yuh}, title = {Scaling of Electron and Ion Transport in the {High-Power} Spherical Torus {NSTX}}, journal = {Physical Review Letters}, year = {2007}, volume = {98}, pages = {175002--4}, number = {17}, month = apr, note = {confinement}, doi = {{10.1103/PhysRevLett.98.175002}}, url = {http://link.aps.org/abstract/PRL/v98/e175002} } @ARTICLE{keidarbeilis, author = {Keidar, Michael and Beilis, Isak L.}, title = {Electron Transport Phenomena in Plasma Devices with E x B Drift}, journal = {IEEE Transactions on Plasma Science}, year = {2005}, volume = {34}, pages = {804-814}, number = {3}, keywords = {hall thruster, electron transport, review, 1yr_project}, owner = {egranste}, timestamp = {2007.05.16} } @ARTICLE{keidar_magnetic_2005, author = {M. Keidar and I. D. Boyd}, title = {On the magnetic mirror effect in Hall thrusters}, journal = {Applied Physics Letters}, year = {2005}, volume = {87}, pages = {121501-3}, keywords = {magnetic mirrors,plasma accelerators,plasma magnetohydrodynamics,plasma sheaths}, url = {http://link.aip.org/link/?APL/87/121501/1} } @ARTICLE{kessel_improved_1994, author = {C. Kessel and J. Manickam and G. Rewoldt and W. M. Tang}, title = {Improved plasma performance in tokamaks with negative magnetic shear}, journal = {Physical Review Letters}, year = {1994}, volume = {72}, pages = {1212}, number = {8}, month = feb, note = {reversed shear}, abstract = {A tokamak plasma configuration is reported that simultaneously improves on the maximum stable plasma pressure, the bootstrap current contribution, and kinetic stability to temperature and density gradient driven modes in toroidal geometry. It is characterized by negative magnetic shear in the plasma interior and a peaked pressure profile. Stability to the ideal low-n external kink modes requires a conducting shell at 1.3 times the plasma minor radius. This novel plasma configuration is promising for improved plasma performance in advanced tokamak experiments.}, doi = {{10.1103/PhysRevLett.72.1212}}, url = {http://link.aps.org/abstract/PRL/v72/p1212} } @INBOOK{sanchez_low-power_HT_2000, pages = {47}, title = {Progress in Astronautics and Aeronautics}, publisher = {AIAA}, year = {2000}, editor = {M.~M. Micci and A.~D. Ketsdever}, author = {V. Khayms and M. Mart\'inez-S\'anchez}, volume = {187}, address = {Reston, VA}, owner = {erikg}, timestamp = {2008.03.31} } @ARTICLE{khudik_longitudinal_1997, author = {V.N. Khudik}, title = {Longitudinal losses of electrostatically confined particles from a mirror device with arbitrary mirror ratio}, journal = {Nuclear Fusion}, year = {1997}, volume = {37}, pages = {189-198}, abstract = {The longitudinal losses of charged particles from a mirror device with an arbitrary mirror ratio are calculated in a systematic way by using a linearized Fokker-Planck equation}, doi = {10.1088/0029-5515/37/2/I03}, issn = {0029-5515} } @ARTICLE{kim_mhd_1999, author = {J. S. Kim and D. H. Edgell and J. M. Greene and E. J. Strait and M. S. Chance}, title = {MHD mode identification of tokamak plasmas from Mirnov signals}, journal = {Plasma Physics and Controlled Fusion}, year = {1999}, volume = {41}, pages = {1399-1420}, abstract = {Identification of coherent waves from fluctuating tokamak plasmas is important for the understanding of magnetohydrodynamics (MHD) behaviour of the plasma and its control. Toroidicity, plasma shaping, uneven distances between the resonant surfaces and detectors, and non-circular conducting wall geometry have made mode identification difficult and complex, especially in terms of the conventional toroidal and poloidal mode numbers, which we call (m,n)-identification. Singular value decomposition (SVD), without any assumption of the basis vectors, determines its own basis vectors representing the fluctuation data in the directions of maximum coherence. Factorization of a synchronized set of spatially distributed data leads to eigenvectors of time- and spatial-covariance matrices, with the energy content of each eigenvector. SVD minimizes the number of significant basis vectors, reducing noise, and minimizes the data storage required to restore the fluctuation data. For sinusoidal signals, SVD is essentially the same as spectral analysis. When the mode has non-smooth structures the advantage of not having to treat all its spectral components is significant in analysing mode dynamics and in data storage. From time SVD vectors, we can see the evolution of each coherent structure. Therefore, sporadic or intermittent events can be recognized, while such events would be ignored with spectral analysis. We present the use of SVD to analyse tokamak magnetic fluctuation data, time evolution of MHD modes, spatial structure of each time vector, and the energy content of each mode. If desired, the spatial SVD vectors can be least-square fit to specific numerical predictions for the (m,n) identification. A phase-fitting method for (m,n) mode identification is presented for comparison. Applications of these methods to mode locking analysis are presented.}, doi = {10.1088/0741-3335/41/11/307}, issn = {0741-3335}, url = {http://www.iop.org/EJ/abstract/0741-3335/41/11/307} } @ARTICLE{kim_negative_1995, author = {J. Y. Kim and M. Wakatani}, title = {Negative shear effect on toroidal ion temperature gradient mode}, journal = {Physics of Plasmas}, year = {1995}, volume = {2}, pages = {1012--1014}, number = {3}, month = mar, doi = {10.1063/1.871407}, keywords = {{DRIFT} {WAVES,} {INSTABILITY} {GROWTH} {RATES,} {ION} {TEMPERATURE,} {PLASMA} {DRIFT,} {PLASMA} {MICROINSTABILITIES,} {STABILIZATION,} {TEMPERATURE} {GRADIENTS,} {TOKAMAK} {DEVICES,} {TOROIDAL} {CONFIGURATION,} {TRANSPORT} {THEORY}}, url = {http://link.aip.org/link/?PHP/2/1012/1} } @ARTICLE{kim_main_1998, author = {Kim, Vladimir}, title = {Main Physical Features and Processes Determining the Performance of Stationary Plasma Thrusters}, journal = {Journal of Propulsion and Power}, year = {1998}, volume = {14}, pages = {736--743}, number = {5}, owner = {erikg}, timestamp = {2008.03.27}, url = {http://pdf.aiaa.org/getfile.cfm?urlX=2%3CWIG7D%2FQKU%3E6B5%3AKF5%2B%5BQZC%3A%0A&urla=%25%2ARH%23%22P%20%20%0A&urlb=%21%2A%20%20%20%0A&urlc=%21%2A0%20%20%0A&urld=%21%2A0%20%20%0A&urle=%27%2B2P%26%23P%2EKU%40%20%20%0A} } @ARTICLE{kingdon_removal_1923, author = {KH Kingdon and I. Langmuir}, title = {The removal of thorium from the surface of a thoriated tungsten filament by positive ion bombardment}, journal = {PHYSICAL REVIEW}, year = {1923}, volume = {22}, pages = {148-160}, number = {2}, month = aug, issn = {0031-899X}, keywords = {thorium,tungsten, 1yr_project} } @ARTICLE{kinsey_first_2008, author = {J. E. Kinsey and G. M. Staebler and R. E. Waltz}, title = {The first transport code simulations using the trapped {gyro-Landau-fluid} model}, journal = {Physics of Plasmas}, year = {2008}, volume = {15}, pages = {055908--14}, number = {5}, month = may, doi = {10.1063/1.2889008}, keywords = {ballooning instability, discharges (electric), plasma confinement, plasma simulation, plasma transport processes, plasma turbulence, Tokamak devices}, url = {http://link.aip.org/link/?PHP/15/055908/1} } @ARTICLE{kinsey_glf23_renorm_2003, author = {Jonathan E.~Kinsey and Gary M.~Staebler and Ronald E.~Waltz}, title = {Burning Plasma Confinement Projections and Renormalization of the GLF23 Drift-Wave Transport Model}, journal = {Fusion Science and Technology}, year = {2003}, volume = {44}, pages = {763--775}, number = {4}, month = {DEC}, abstract = {Fusion power predictions are presented using the GLF23 drift-wave transport model for several next-step tokamak designs including ITER, FIRE, and IGNITOR. The GLF23 model has been renormalized using recent gyrokinetic simulations and a database of nearly 50 H-mode discharges from three different tokamaks. The renormalization reduces the ion temperature gradient/trapped electron mode (ITG/TEM)-driven transport by a factor of 3.7 while electron temperature gradient (ETG) mode transport is increased by a factor of 4.8 with respect to the original model. Using the renormed model, the fusion power performance is uniformly assessed, and the pedestal requirements are summarized for each device. The renormed model is still quite stiff and yields somewhat more optimistic predictions for next-step burning plasma experiments. The consequences of stiff transport in the plasma core are discussed. A fusion fit formula is derived whereby the GLF23 results follow a universal stiff model curve for the normalized fusion power versus pedestal temperature.}, keywords = {GLF23, transport modelling, ITER, GYRO, gyrokinetic}, owner = {erikg}, timestamp = {2009.08.21}, url = {http://epubs.ans.org/?a=414} } @ARTICLE{klinger_chaos_1997, author = {T. Klinger and A. Latten and A. Piel and G. Bonhomme and T. Pierre}, title = {Chaos and turbulence studies in low- plasmas}, journal = {Plasma Physics and Controlled Fusion}, year = {1997}, volume = {39}, pages = {B145-B156}, note = {Reference from Turbulence course, Zweben's 1st lecture. Measures ion saturation current from Langmuir probe array and examines with the tools of nonlinear dynamics. The rotation frequency is on the same order as the diamagnetic drift frequency. Key finding is that the transition to turbulence is driven "by the nonlinear interaction of a few drift modes as well as the boundary conditions". Four stages depending on the control parameter (the grid voltage): fixed point, limit cycle, 2d torus, mode locked (1d), chaos with structure, turbulent with points in phase space scattered homogeneously.}, abstract = {This paper describes recent experimental investigations of the nonlinear dynamics of collisional current-driven drift waves in a linear low- discharge. It is shown that the bias of an injection grid leads to rigid-body rotation of the cylindrical plasma column that strongly destabilizes the drift waves, thus providing a control parameter for the drift-wave dynamics. In the nonlinear regime, when the control parameter is increased, the transition scenario from stability to weakly developed turbulence is studied. Two successive Hopf bifurcations, a mode-locked state and its gradual destabilization to chaos and finally turbulence follow the classical Ruelle - Takens transition scenario known from neutral fluids. In addition to the temporal dynamics, the spatiotemporal evolution of drift waves is studied by means of circular Langmuir probe arrays with high spatial and temporal resolution. With each Hopf bifurcation, a drift-mode onset is associated and the bifurcation from quasi-periodicity to mode locking corresponds to the transition from non-resonant to resonant mode interaction. The mode-locked state forms a persistent spatiotemporal pattern that is destabilized by the occurrence of defects. In contrast, the turbulent state is a fully disordered, intermittent state.}, doi = {10.1088/0741-3335/39/12B/012}, issn = {0741-3335}, url = {http://www.iop.org/EJ/abstract/0741-3335/39/12B/012} } @BOOK{kohl_handbook_1995, title = {Handbook of materials and techniques for vacuum devices}, publisher = {American Institute of Physics}, year = {1995}, author = {Walter H. Kohl}, series = {American Vacuum Society Classics}, address = {New York}, comment = {Furth Library TK7835 .K6}, keywords = {cathode,filament,thermionic,vacuum,tungsten} } @ARTICLE{kotschenreuther_quantitative_1995, author = {M. Kotschenreuther and W. Dorland and M. A. Beer and G. W. Hammett}, title = {Quantitative predictions of tokamak energy confinement from first-principles simulations with kinetic effects}, journal = {Physics of Plasmas}, year = {1995}, volume = {2}, pages = {2381--2389}, number = {6}, month = jun, doi = {10.1063/1.871261}, keywords = {{BALLOONING} {INSTABILITY,} {ELECTRON} {TEMPERATURE,} {ION} {TEMPERATURE,} {PLASMA} {CONFINEMENT,} {PLASMA} {SIMULATION,} {TFTR} {TOKAMAK,} {TRANSPORT} {THEORY,} {TURBULENCE}}, url = {http://link.aip.org/link/?PHP/2/2381/1} } @ARTICLE{kotschenreuther_comparison_1995, author = {Mike Kotschenreuther and G. Rewoldt and W. M. Tang}, title = {Comparison of initial value and eigenvalue codes for kinetic toroidal plasma instabilities}, journal = {Computer Physics Communications}, year = {1995}, volume = {88}, pages = {128--140}, number = {2-3}, month = aug, abstract = {In plasma physics, linear instability calculations can be implemented either as initial value calculations or as eigenvalue calculations. Here, comparisons between comprehensive linear gyrokinetic calculations employing the ballooning formalism for high-n (toroidal mode number) toroidal instabilities are described. One code implements an initial value calculation on a grid using a Lorentz collision operator and the other implements an eigenvalue calculation with basis functions using a Krook collision operator. An electrostatic test case with artificial parameters for the toroidal drift mode destabilized by the combined effects of trapped particles and an ion temperature gradient has been carefully analyzed both in the collisionless limit and with varying collisionality. Good agreement is found. Results from applied studies using parameters from the Tokamak Fusion Test Reactor {(TFTR)} experiment are also compared.}, doi = {{10.1016/0010-4655(95)00035-E}}, issn = {0010-4655}, url = {http://www.science-direct.com/science/article/B6TJ5-40324V5-3/2/f5dfd72ad0f6e747cf2cb934e3d9fc26} } @ARTICLE{kraft_analysis_2006, author = {D. J. Kraft and Roger D. Bengtson and B. N. Breizman and D. G. Chavers and C. C. Dobson and J. E. Jones and V. T. Jacobson}, title = {Analysis of multifrequency interferometry in a cylindrical plasma}, journal = {Rev. Sci. Instrum.}, year = {2006}, volume = {77}, pages = {10E910--3}, month = oct, note = {takes into account finite beam size relative to plasma size}, doi = {10.1063/1.2222172}, keywords = {interferometers,microwave detectors,plasma density,plasma diagnostics,plasma electromagnetic wave propagation}, url = {http://link.aip.org/link/?RSI/77/10E910/1} } @BOOK{kralladvancesplasmaphysics, title = {Advances in Plasma Physics}, year = {1968}, author = {N. Krall}, volume = {1}, keywords = {GPP2, collisionless drift waves, universal drift instability}, owner = {erikg}, timestamp = {2007.05.09} } @ARTICLE{kramer_2d_2006, author = {G.J. Kramer and R. Nazikian and E.J. Valeo and R.V. Budny and C. Kessel and D. Johnson}, title = {2D reflectometer modelling for optimizing the ITER low-field side X-mode reflectometer system}, journal = {Nuclear Fusion}, year = {2006}, volume = {46}, pages = {S846-S852}, abstract = {The response of a low-field side X-mode reflectometer system for ITER is simulated with a 2D reflectometer code using a realistic plasma equilibrium. Relativistic corrections to the plasma permitivity due to the high electron temperature were included. It is found that the reflected beam will often miss its launch point by as much as 40 cm and that a vertical array of receiving antennas is essential in order to observe a reflection on the low-field side of ITER. Relativistic absorption effects were studied with a 1D full wave code and found to be insignificant for reflections from the low-field side up to the plasma centre.}, doi = {10.1088/0029-5515/46/9/S21}, issn = {0029-5515}, url = {http://www.iop.org/EJ/toc/0029-5515/46/9} } @ARTICLE{kramer_correlation_rsi_2003, author = {G. J. Kramer and R. Nazikian and E. Valeo}, title = {Correlation reflectometry for turbulence and magnetic field measurements in fusion plasmas (invited)}, journal = {Review of Scientific Instruments}, year = {2003}, volume = {74}, pages = {1421-1425}, month = mar, note = {Papers from the 14th Topical Conference on High Temperature Plasma Diagnostics, Madison, Wisconsin}, address = {Madison (Wisconsin)}, booktitle = {Papers from the 14th Topical Conference on High Temperature Plasma Diagnostics}, doi = {10.1063/1.1530380}, keywords = {correlation methods,fusion reactor theory,magnetic field measurement,microwave reflectometry,plasma diagnostics,plasma fluctuations,plasma simulation,plasma toroidal confinement,plasma turbulence}, publisher = {AIP}, url = {http://link.aip.org/link/?RSI/74/1421/1} } @ARTICLE{kramer_simulation_2004, author = {G. J. Kramer and R. Nazikian and E. J. Valeo}, title = {Simulation of optical and synthetic imaging using microwave reflectometry}, journal = {Plasma Physics and Controlled Fusion}, year = {2004}, volume = {46}, pages = {695-710}, abstract = {Two-dimensional full-wave time-dependent simulations in full plasma geometry are presented, which show that conventional reflectometry (without a lens) can be used to synthetically image density fluctuations in fusion plasmas under conditions where the parallel correlation length greatly exceeds the poloidal correlation length of the turbulence. The advantage of synthetic imaging is that the image can be produced without the need for a large lens of high optical quality, and each frequency that is launched can be independently imaged. A particularly simple arrangement, consisting of a single receiver located at the midpoint of a microwave beam propagating along the plasma midplane is shown to suffice for imaging purposes. However, as the ratio of the parallel to poloidal correlation length decreases, a poloidal array of receivers needs to be used to synthesize the image with high accuracy. Simulations using DIII-D relevant parameters show the similarity of synthetic and optical imaging in present day experiments.}, doi = {10.1088/0741-3335/46/4/009}, issn = {0741-3335} } @ARTICLE{krasheninnikov_scrape_2001, author = {S. I. Krasheninnikov}, title = {On scrape off layer plasma transport}, journal = {Physics Letters A}, year = {2001}, volume = {283}, pages = {368-370}, month = may, abstract = {Qualitative physical picture describing fast convective radial plasma transport in tokamak scrape off layer is suggested. It is based on the hypothesis of detachment of high density plasma blobs from the bulk plasma due to turbulence effects resulting in plasma stratification in the region around separatrix. These blobs extended along the magnetic field lines and having rather small cross-section in the perpendicular plane, propagate to the outer wall due to [backward difference]B plasma polarization and associated drift.}, doi = {10.1016/S0375-9601(01)00252-3}, url = {http://www.sciencedirect.com/science/article/B6TVM-4349XVR-K/2/48fdf6144faf48085b6232f847795875} } @ARTICLE{krasheninnikov_strongly_2009, author = {S. I. Krasheninnikov and A. Yu. Pigarov and T. K. Soboleva and D. L. Rudakov}, title = {Strongly intermittent edge plasma transport: Issues with modeling and interpretation of experimental data}, journal = {Physics of Plasmas}, year = {2009}, volume = {16}, pages = {014501--4}, number = {1}, doi = {10.1063/1.3050076}, keywords = {plasma boundary layers,plasma magnetohydrodynamics,plasma nonlinear processes,plasma transport processes}, url = {http://link.aip.org/link/?PHP/16/014501/1} } @ARTICLE{kreischer_single-mode_1987, author = {K. E. Kreischer and R. J. Temkin}, title = {Single-mode operation of a high-power, step-tunable gyrotron}, journal = {Physical Review Letters}, year = {1987}, volume = {59}, pages = {547}, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, url = {http://link.aps.org/abstract/PRL/v59/p547} } @ARTICLE{kugel_physics_????, author = {{H.W.} Kugel and M. Bell and L. Berzak and A. Brooks and R. Ellis and S. Gerhardt and H. Harjes and R. Kaita and J. Kallman and R. Maingi and R. Majeski and D. Mansfield and J. Menard and {R.E.} Nygren and V. Soukhanovskii and D. Stotler and P. Wakeland and {L.E.} Zakharov}, title = {Physics design requirements for the National Spherical Torus Experiment liquid lithium divertor}, journal = {Fusion Engineering and Design}, volume = {In Press, Corrected Proof}, abstract = {Recent National Spherical Tokamak Experiment {(NSTX)} high-power divertor experiments have shown significant and recurring benefits of solid lithium coatings on plasma facing components {(PFCs)} to the performance of divertor plasmas in both L- and H-mode confinement regimes heated by high-power neutral beams. The next step in this work is installation of a liquid lithium divertor {(LLD)} to achieve density control for inductionless current drive capability (e.g., about a 15-25\% ne decrease from present highest non-inductionless fraction discharges which often evolve toward the density limit, {ne/nGW} {\textasciitilde} 1), to enable ne scan capability (×2) in the H-mode, to test the ability to operate at significantly lower density (e.g., {ne/nGW} = 0.25), for future reactor designs based on the Spherical Tokamak, and eventually to investigate high heat-flux power handling (10 {MW/m2)} with long pulse discharges ({\textgreater}1.5 s). The first step {(LLD-1)} physics design encompasses the desired plasma requirements, the experimental capabilities and conditions, power handling, radial location, pumping capability, operating temperature, lithium filling, {MHD} forces, and diagnostics for control and characterization.}, doi = {10.1016/j.fusengdes.2008.11.102}, issn = {0920-3796}, keywords = {{Divertors,Lithium,Lithium} wall fusion regime}, url = {http://www.sciencedirect.com/science/article/B6V3C-4VF4YTK-1/2/4b5a844e76b8bc33906f965829a68ab9} } @ARTICLE{labombard_transport-driven_2004, author = {B. {LaBombard} and {J.E.} Rice and {A.E.} Hubbard and {J.W.} Hughes and M. Greenwald and J. Irby and Y. Lin and B. Lipschultz and {E.S.} Marmar and {C.S.} Pitcher and N. Smick and {S.M.} Wolfe and {S.J.} Wukitch and the Alcator Group}, title = {Transport-driven {Scrape-Off-Layer} flows and the boundary conditions imposed at the magnetic separatrix in a tokamak plasma}, journal = {Nuclear Fusion}, year = {2004}, volume = {44}, pages = {1047--1066}, number = {10}, abstract = {Plasma profiles and flows in the low- and high-field side scrape-off-layer {(SOL)} regions in Alcator {C-Mod} are found to be remarkably sensitive to magnetic separatrix topologies (upper-, lower- and double-null) and to impose topology-dependent flow boundary conditions on the confined plasma. Near-sonic plasma flows along magnetic field lines are observed in the high-field {SOL,} with magnitude and direction clearly dependent on X-point location. The principal drive mechanism for the flows is a strong ballooning-like poloidal transport asymmetry: parallel flows arise so as to re-symmetrize the resulting poloidal pressure variation in the {SOL.} Secondary flows involving a combination of toroidal rotation and {Pfirsch-Schluter} ion currents are also evident. As a result of the transport-driven parallel flows, the {SOL} exhibits a net co-current (counter-current) volume-averaged toroidal momentum when B x {[?]B} is towards (away from) the X-point. Depending on the discharge conditions, flow momentum can couple across the separatrix and affect the toroidal rotation of the confined plasma. This mechanism accounts for a positive (negative) increment in central plasma co-rotation seen in L-mode discharges when B x {[?]B} is towards (away from) the X-point. Experiments in ion-cyclotron range-of-frequency-heated discharges suggest that topology-dependent flow boundary conditions may also play a role in the sensitivity of the {L-H} power threshold to X-point location: in a set of otherwise similar discharges, the {L-H} transition is seen to be coincident with central rotation achieving roughly the same value, independent of magnetic topology. For discharges with B x {[?]B} pointing away from the X-point (i.e. with the {SOL} flow boundary condition impeding co-current rotation), the same characteristic rotation can only be achieved with higher input power.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/44/10/001/} } @ARTICLE{lang_gyrokinetic_2007, author = {Jianying Lang and Yang Chen and Scott E. Parker}, title = {Gyrokinetic delta f particle simulation of trapped electron mode driven turbulence}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {082315--12}, number = {8}, doi = {10.1063/1.2771141}, keywords = {electrons, plasma instability, plasma simulation, plasma transport processes, plasma turbulence, TEM}, url = {http://link.aip.org/link/?PHP/14/082315/1} } @ARTICLE{langmuir_electron_1923, author = {I. Langmuir}, title = {The electron emission from thoriated tungsten filaments}, journal = {PHYSICAL REVIEW}, year = {1923}, volume = {22}, pages = {0357-0398}, number = {4}, month = oct, issn = {0031-899X}, keywords = {thermionic emission, tungsten, 1yr_project} } @ARTICLE{lanier_investigation_2001, author = {N. E. Lanier and D. Craig and J. K. Anderson and T. M. Biewer and B. E. Chapman and D. J. Den Hartog and C. B. Forest and S. C. Prager and D. L. Brower and Y. Jiang}, title = {An investigation of density fluctuations and electron transport in the Madison Symmetric Torus reversed-field pinch}, journal = {Physics of Plasmas}, year = {2001}, volume = {8}, pages = {3402}, number = {7}, doi = {10.1063/1.1378328}, issn = {{1070664X}}, url = {http://link.aip.org/link/PHPAEN/v8/i7/p3402/s1&Agg=doi} } @ARTICLE{laqua_electron_2007, author = {Heinrich Peter Laqua}, title = {Electron Bernstein wave heating and diagnostic}, journal = {Plasma Physics and Controlled Fusion}, year = {2007}, volume = {49}, pages = {R1--R42}, number = {4}, note = {{EBW}}, abstract = {This paper gives a review on the experiments with electron Bernstein waves {(EBWs)} in fusion devices. The different methods of {EBW} generation are described and compared with experimental results. The influence of density fluctuation and parametric instability on the conversion efficiency is discussed. The related experiments are reported. The {EBW} propagation is calculated by ray-tracing codes. The results are used to analyse {EBW} emission, heating and current drive experiments in stellarators and tokamaks. With high power microwave sources {EBWs} have been excited over a wide range of frequencies for plasma heating and current drive. The experimental results demonstrated that {EBW} can efficiently heat over-dense plasmas. The local power deposition allows the generation of heat waves for transport studies. Due to their electrostatic character, {EBWs} can achieve parallel refractive indices {(N{\textbar}{\textbar})} larger than 1, which is favourable for efficient current drive. This could be confirmed by a first current drive experiment. The {EBWs} also express a strong cyclotron damping, which enabled efficient heating at higher harmonics in several experiments.}, issn = {0741-3335}, url = {http://www.iop.org/EJ/abstract/0741-3335/49/4/R01/} } @ARTICLE{laqua_electron_1998, author = {H. P. Laqua and H. J. Hartfu{\textbackslash}ss and {W7-AS} Team}, title = {Electron Bernstein Wave Emission from an Overdense Plasma at the {W7-AS} Stellarator}, journal = {Physical Review Letters}, year = {1998}, volume = {81}, pages = {2060}, number = {10}, note = {{EBW}}, abstract = {Thermal electron Bernstein wave {(EBW)} radiation of an overdense plasma (ne{\textgreater}ne,cutoff) was measured with an oblique viewing angle at the {W7-AS} stellarator. The spectrum consists of a local cyclotron-emission part and a nonlocal high-frequency part. Edge-temperature perturbations excited by carbon injection were used to demonstrate the relation between frequency and position of emission. Since for {EBW's} no density limit exists, the operation window of the electron-cyclotron-emission diagnostic can be extended to densities above the cutoff density.}, doi = {{10.1103/PhysRevLett.81.2060}}, url = {http://link.aps.org/abstract/PRL/v81/p2060} } @ARTICLE{lawson_criteria_1957, author = {Lawson, J.D.}, title = {Some criteria for a power producing thermonuclear reactor}, journal = {Proceedings of the Physical Society}, year = {1957}, volume = {B70}, pages = {6}, owner = {erikg}, timestamp = {2009.07.15} } @ARTICLE{lee_exact_2007, author = {Dongsoo Lee and Lutfi Oksuz and Noah Hershkowitz}, title = {Exact Solution for the Generalized Bohm Criterion in a Two-Ion-Species Plasma}, journal = {Physical Review Letters}, year = {2007}, volume = {99}, pages = {155004-4}, month = oct, url = {http://link.aps.org/abstract/PRL/v99/e155004} } @ARTICLE{lee_gyrokinetic_1983, author = {W. W. Lee}, title = {Gyrokinetic approach in particle simulation}, journal = {Physics of Fluids}, year = {1983}, volume = {26}, pages = {556-562}, month = feb, doi = {10.1063/1.864140 }, keywords = {algorithms,electrostatics,gyrokinetic,kinetic,larmor radius,nonlinear problems,particles,plasma,plasma microinstabilities,simulation,slabs}, url = {http://link.aip.org/link/?PFL/26/556/1} } @ARTICLE{lehnert_rotating_1971, author = { B LEHNERT}, title = {ROTATING PLASMAS}, journal = {NUCLEAR FUSION}, year = {1971}, volume = {11}, pages = {485-\&}, issn = {0029-5515}, url = {http://apps.isiknowledge.com/full\_record.do?product=WOS\&search\_mode=GeneralSearch\&qid=3\&SID=1Bdih3pjmF9joCjjHAB\&page=1\&doc=8} } @ARTICLE{lemoine:092301, author = {Nicolas Lemoine and Dominique M. Gr\'{e}sillon}, title = {Plasma diffusion across a magnetic field observed by collective light scattering: Experimental evidence for L[e-acute]vy stable distributions}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {092301}, number = {9}, eid = {092301}, note = {Uses a continuous time random walk (CTRW) model and Levy stable distributions to explain the transport properties measured with collective light scattering. The scattered electric field complex amplitude is proportional to the space FT fo the electron density. The scattered light intensity is directly related to the static form factor, which can be calculated by an integration fo the experimental spectra over the time frequency. The detector photon noise is used to get an absolute value fo the static form factor so that amplitudes actual amplitudes of the fluctuations can be measured. They made the approx that the turbulence is convective (density inhomogeneities convected by mass motion), which is justified by measurements that show fast decay of the form factor with wavenumber indicating energy is mostly at larger scales. The density fluctuation level was measured with a Langmuir probe biased in the ion saturation region. Adding a small vertical field to the purely toroidal field was successful in removing drifts. This is important, because as the instrument gives a volume-integrated measurement, if there are 2+ regions with different fluid velocities, there will be two peaks which might overlap, complicating the analysis. Therefore it is important to get a plasma as homogeneous as possible at large scales. Once drifts have been removed, the time series spectra at different k are similar: freq is max at zero and width increases linearly with k, which is characteristic of a convective motion spectra without phase velocity. The fluctuation level is so large above EQU that a linear relation between parameters (such as density and velocity) is very unlikely. This allows k vector components to be treated as uncorrelated, and the plasma displacement probability distribution can be determined from the measurements. At short times, a gaussian PDF (implicityly assumed with a fick model for diffusion) works ok, but at long times, a Levy distribution, with $E_c(k_\tau_0)=-ln{C_N(k,\tau)}=bk^\alpha$ with $\alpha \approx 1$ works much better, ie. a long-tailed dist function where extreme events are more likely.}, doi = {10.1063/1.2010308}, keywords = {plasma transport processes; plasma diagnostics; plasma toroidal confinement; discharges (electric); plasma turbulence; Fourier transforms; plasma density; plasma fluctuations; diagnostics}, numpages = {9}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/12/092301/1} } @ARTICLE{_implicit_2005, author = {Mohammed Lemou and Luc Mieussens}, title = {Implicit Schemes for the Fokker--Planck--Landau Equation}, journal = {SIAM Journal on Scientific Computing}, year = {2005}, volume = {27}, pages = {809}, doi = {10.1137/040609422}, issn = {10648275} } @ARTICLE{levinton_improved_1995, author = {F. M. Levinton and M. C. Zarnstorff and S. H. Batha and M. Bell and R. E. Bell and R. V. Budny and C. Bush and Z. Chang and E. Fredrickson and A. Janos and J. Manickam and A. Ramsey and S. A. Sabbagh and G. L. Schmidt and E. J. Synakowski and G. Taylor}, title = {Improved Confinement with Reversed Magnetic Shear in {TFTR}}, journal = {Physical Review Letters}, year = {1995}, volume = {75}, pages = {4417}, number = {24}, month = dec, abstract = {A new tokamak confinement regime has been observed on the Tokamak Fusion Test Reactor {(TFTR)} where particle and ion thermal diffusivities drop precipitously by a factor of ∼40 to the neoclassical level for the particles and to much less than the neoclassical value for the ions in the region with reversed shear. This enhanced reversed shear confinement mode allows the central electron density to rise from 0.45 × 1020 m-3 to ∼1.2 × 1020 m-3 with Ti∼24 {keV} and Te∼8 {keV.} This regime holds promise for significantly improved tokamak performance.}, doi = {{10.1103/PhysRevLett.75.4417}}, url = {http://link.aps.org/abstract/PRL/v75/p4417} } @BOOK{lichtenberg_regular_1992, title = {Regular and Chaotic Dynamics}, publisher = {Springer-Verlag}, year = {1992}, author = {Allan J Lichtenberg and M. A Lieberman and Allan J Lichtenberg}, pages = {692}, address = {New York}, edition = {2nd ed}, isbn = {0387977457}, keywords = {Hamiltonian systems,Nonlinear oscillations,Stochastic processes} } @ARTICLE{lidsky_highly_1962, author = {LM LIDSKY and DJ ROSE and S. YOSHIKAWA and SD ROTHLEDER and RJ MACKIN and C. MICHELSON}, title = {HIGHLY IONIZED HOLLOW CATHODE DISCHARGE}, journal = {Journal of Applied Physics}, year = {1962}, volume = {33}, pages = {2490-\&}, issn = {0021-8979}, keywords = {Physics, Applied} } @ARTICLE{lidsky1962, author = {Lidsky, L.M., and Rothleder, S.D., and Rose, D.J., and Yoshikawa, S.}, title = {Highly Ionized Hollow Cathode Discharge}, journal = {Journal of Applied Physics}, year = {1962}, volume = {33}, pages = {2490-2497}, number = {8}, month = aug, note = {Gives balancing eqns and shows that most electrons are from thermionic emission.}, file = {\\Docs\\hollow cathode\\lidsky1962.pdf:\\Docs\\hollow cathode\\lidsky1962.pdf:PDF}, keywords = {hollow cathode, 1yr_project}, owner = {egranste}, timestamp = {2007.05.16} } @BOOK{liebermanlichtenberg, title = {Principles of Plasma Discharges and Materials Processing}, publisher = {John Wiley and Sons}, year = {2005}, author = {Michael A. Lieberman and Allan J. Lichtenberg}, edition = {2}, note = {Chapter 6.6 Electrostatic Probe Diagnostics: Cylindrical probe with collisionless sheath Conservation of angular momentum puts limits on the $v_\phi$ integral, ie. only charges below a certain azimuthal velocity at the sheath edge hit the probe. For a maxwellian distribution: $I=2en_s ad\left( \frac{2e(\Phi_p-V_B)}{m} \right)^{1/2}$, ie. $I^2$ is linear with bias voltage.}, comment = {QC718.5.D9 L54 2005}, keywords = {sheath, low-temperature, gas discharge}, owner = {egranste}, timestamp = {2007.04.13} } @ARTICLE{lieberman06, author = {{M. A.} Lieberman and C. Charles and {R. W.} Boswell}, title = {A theory for formation of a low pressure, current-free double layer}, journal = {J. Phys. D: Appl. Phys.}, year = {2006}, volume = {39}, pages = {3294-3304}, note = {Abstract has a good summary. This theory couples the diffusive flows of the quasi-neutral plasmas in the source and diffusion (expansion) chamber with the dynamics of the particles in the non-neutral DL. Particle balance upstream determines $\Phi_{DL}$. Using space-charge limited flow, Langmuir showed that if $I_e = \sqrt{M/m}I_e$, then the sum of the charge density between a gap with an electron-emitting cathode and an ion-emitting anode would vanish. To treat the current-free DL, it is assumed that electrons accelerated upstream are almost entirely reflected from teh ened wall of the source region, forming a counter-streaming population. At low pressures, the ionization rates are equal across the DL, but because of its smaller radius, the particle loss rate is greater upstream; the additional ionization rate required upstream is supplied by the accelerated electron group. Using flux conservation, Boltzman's law, conservation of energy, and assuming half-Maxwellian electrons, etc. equations for relative charge densities and entry velocities as a function of DL strength are determined. The accelerated ion group enters the DL at about 1.2-1.3 $u_B$, while the velocity for the lowest energy electron in the accelerating group is 0.2-1 $u_{Be}=\sqrt{eT_i/m}$. A ratio of electron to ion flux for the accelerating species is derived, and found to e less significantly less than the Langmuir ratio at low to moderate DL strengths. The author claims that it is easy to see that adding an electron group that is reflected at the wall contributes the same charge density as the oridignal group, ie. the DL solution is unaltered and in this sense there is no fundamental distinction between a current-carrying and current-free DL. The slight imbalance in the incident and reflected accelerated electrons balances the loss of ions to the upstream wall. Using low-pressure diffusion theory for this experimental geometry, an expression for $\Phi_{DL}$ in terms of the densities and diffusion coeffs is found. DL strength increases to a maximum as pressure is decreased, until pressure drops to a critical value at which point accelerated electrons upstream cannot balance the excess upstream particle losses. The DL disappears at high pressures, because when the ratio of downstream-to-upstream ionization rates becomes equal to the ratio of particle loss rates, te additional ionization by the electrons accelerated upstream is not needed.}, abstract = {A theory is developed for the formation of a low pressure, current-free double layer just inside an upstream dielectric source chamber connected to a larger diameter, downstream metallic expansion chamber. The double layer is described using four groups of charged particle: thermal ions, mono-energetic accelerated ions flowing downstream, accelerated electrons flowing upstream and thermal electrons. The accelerated electrons are formed downstream from an initially nearly half-Maxwellian electron distribution. A fifth group of counter-streaming electrons formed by the reflection of the accelerated electrons from the sheath at the insulated end wall of the source chamber is used to enforce the condition that the double layer be current-free. The condition of particle balance upstream is found to determine the double layer potential. The double layer is found to disappear at very low pressures due to loss of ionization balance upstream and due to energy relaxation processes for ionizing electrons at higher pressures. The theory is found to be in good agreement with the experiments.}, file = {\\Docs\\Double Layers\\lieberman06.pdf:\\Docs\\Double Layers\\lieberman06.pdf:PDF}, keywords = {double layer, 1yr_project} } @ARTICLE{lin_vertical_2006, author = {L. Lin and E. M. Edlund and M. Porkolab and Y. Lin and S. J. Wukitch}, title = {Vertical localization of phase contrast imaging diagnostic in Alcator {C-Mod}}, journal = {Rev. Sci. Instrum.}, year = {2006}, volume = {77}, pages = {10E918--3}, month = oct, doi = {10.1063/1.2228623}, keywords = {plasma density,plasma diagnostics,plasma fluctuations,plasma instability,plasma toroidal {confinement,Tokamak} devices}, url = {http://link.aip.org/link/?RSI/77/10E918/1} } @ARTICLE{linton_dynamics_2006, author = {Mark G. Linton}, title = {Dynamics of magnetic flux tubes in space and laboratory plasmas}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {058301-6}, month = may, keywords = {astrophysical plasma,plasma magnetohydrodynamics}, url = {http://link.aip.org/link/?PHP/13/058301/1} } @ARTICLE{littlejohn_guiding_1979, author = {Robert G. Littlejohn}, title = {A guiding center Hamiltonian: A new approach}, journal = {Journal of Mathematical Physics}, year = {1979}, volume = {20}, pages = {2445-2458}, month = dec, doi = {10.1063/1.524053 }, keywords = {CANONICAL TRANSFORMATIONS,CLASSICAL MECHANICS,EQUATIONS OF MOTION,GUIDING=(HYPHEN)=CENTER APPROXIMATION,HAMILTONIANS,MAGNETIC FIELDS,PERTURBATION THEORY,PHASE SPACE}, url = {http://link.aip.org/link/?JMP/20/2445/1} } @ARTICLE{litvak:1379, author = {Andrei A. Litvak and Nathaniel J. Fisch}, title = {Rayleigh instability in Hall thrusters}, journal = {Physics of Plasmas}, year = {2004}, volume = {11}, pages = {1379-1383}, number = {4}, note = {Derived expressions for Raleigh instability. For growth, there needs to be a point where the wave is in resonance with the flow, and a given parameter vanishes at a point inside the channel.}, abstract = {Gradient-driven Rayleigh-type instabilities in Hall plasma thrusters are analyzed using linearized two-fluid hydrodynamic equations. Necessary instability conditions and a general criterion for stability of azimuthally propagating perturbations are derived. For a simplified model of the axial distribution of parameters inside the thruster channel, the growth rate of an unstable wave, resonant with the azimuthal electron flow, is obtained. The frequency and phase relations are related to the results of experimental investigations of high-frequency oscillations in Hall thrusters.}, doi = {10.1063/1.1647565}, keywords = {plasma instability; plasma waves; plasma magnetohydrodynamics; plasma devices; propulsion; plasma oscillations; 1yr_project}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/11/1379/1} } @ARTICLE{litvak:1701, author = {Andrei A. Litvak and Yevgeny Raitses and Nathaniel J. Fisch}, title = {Experimental studies of high-frequency azimuthal waves in Hall thrusters}, journal = {Physics of Plasmas}, year = {2004}, volume = {11}, pages = {1701-1705}, number = {4}, note = {Used single-tip Langmuir probe with impedance matching circuitry placed inside the vac vessel. Probe was biased negative wrt. $V_p$ simply by connecting it to vessel ground through a load small compared to probe-plasma impedance, but large enough to detect fluctuations without high amplification. Probes mounted at various azimuthal angles, signals were synchronized for comparison. Spectrum was virtually identical for all HT operating regimes and thruster configs. Determined phase relationship between diff azimuthal positions by identifying the main harmonics between 5--50Mhz, then digitally bandpass filtering around the harmonics (generating a sine wave) then fitting the filtered waves to a sine wave and recording the phase shift. The phase shifts turned out to be exactly equal to the angle between the probe azimuthal locations around the thruster demonstrating wave propagation was purely azimuthal. Amplitude of oscillations was unstable. Frequencies were strongly dependent on operating parameters: increased coil current decreased freq (compatible with ExB drift). Also detected in CHT. Measured phase velocity not equal to the electron drift velocity, and no phase velocity dependence on the axial posn of probe indicate an azimuthally rotating plasma density fluctuation was not being observed but rather azimuthally propagating oscillatory modes are present. No statistically-significant correlation between oscillation onset times or burst durations with thruster operating regime. Thought that the observed waves are from a Raleigh instability.}, abstract = {High-frequency oscillations (1100 MHz) are drawing significant attention in the recent research of Hall thrusters. A diagnostic setup, consisting of single Langmuir probe, special shielded probe connector-positioner, and electronic impedance-matching circuit, was successfully built and calibrated. Through simultaneous high-frequency probing of the Hall-thruster plasma at multiple locations, high-frequency plasma waves have been successfully identified and characterized.}, doi = {10.1063/1.1634564}, keywords = {Hall effect devices; plasma waves; plasma oscillations; plasma diagnostics; Langmuir probes; calibration; plasma devices; 1yr_project}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/11/1701/1} } @ARTICLE{2001PhPl....8..648L, author = {{Litvak}, A.~A. and {Fisch}, N.~J.}, title = {{Resistive instabilities in Hall current plasma discharge}}, journal = {Physics of Plasmas}, year = {2001}, volume = {8}, pages = {648-651}, month = feb, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2001PhPl....8..648L}, doi = {10.1063/1.1336531}, keywords = {1yr_project} } @ARTICLE{2001APS..DPPKP1059L, author = {{Litvak}, A. and {Raitses}, Y. and {Fisch}, N.}, title = {{High-frequency instabilities in Hall current plasma thruster}}, journal = {APS Meeting Abstracts}, year = {2001}, pages = {1059P-+}, month = oct, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2001APS..DPPKP1059L}, keywords = {1yr_project} } @ARTICLE{lo_calibration_1997, author = {E. Lo and R. Nazikian and D. Stutman and W. Choe and R. Kaita}, title = {Calibration and test of the tangential phase contrast imaging diagnostic on {CDX-U}}, journal = {Proceedings of the eleventh topical conference on high temperature plasma diagnostics}, year = {1997}, volume = {68}, pages = {1206--1216}, month = feb, doi = {10.1063/1.1147883}, keywords = {{CALIBRATION,CARBON} {DIOXIDE} {LASERS,DENSITY,ELECTRON} {DENSITY,FLUCTUATIONS,IMAGES,MIRRORS,OPTICAL} {SYSTEMS,PLASMA} {DENSITY,PLASMA} {DIAGNOSTICS,plasma} fluctuations,plasma toroidal {confinement,SENSITIVITY,TESTING,TOKAMAK} {DEVICES}}, url = {http://link.aip.org/link/?RSI/68/1206/1} } @ARTICLE{lo_linear_1995, author = {E. Lo and J. Wright and R. Nazikian}, title = {Linear systems description of the {CO2} laser-based tangential imaging system}, journal = {Review of Scientific Instruments}, year = {1995}, volume = {66}, pages = {1180--1183}, number = {2}, month = feb, note = {Show the effect of a tangential beam through a toroidal geometry is that the plasma amplifies small \$k\_x\$ fluctuations, and induces a different phase shift for \$k\_x{\textless}0\$ and \$k\_x{\textgreater}0\$. They show a design of a phase mirror that cuts off for \${\textbar}k\_x{\textbar}{\textless}k\_{x,min}\$ and eliminates the phase distortion. Also derive a contrast enhancement factor: \${\textbackslash}gamma = (1-{\textbackslash}sqrt{(2b{\textasciicircum}2/a{\textasciicircum}2)-1})/{\textbackslash}sqrt{2}\$ for the intensity variation due to a phase variation.}, doi = {10.1063/1.1146002}, keywords = {{CO2} {LASERS,FLUCTUATIONS,IMAGE} {PROCESSING,INFRARED} {RADIATION,LASER} {SPECTROSCOPY,PCI,phase} contrast {imaging,PLASMA} {DIAGNOSTICS,POINT} {SPREAD} {FUNCTIONS}}, url = {http://link.aip.org/link/?RSI/66/1180/1} } @PHDTHESIS{lo_tangential_1997, author = {Ernest P. Lo}, title = {Tangential phase contrast imaging diagnostic for density fluctuation measurement on {CDX-U}}, school = {Princeton University}, year = {1997}, note = {{Ph.D.}}, comment = {Understanding the nature and effects of turbulence is one of the central efforts in fusion science. Spatially resolved measurement of turbulent fluctuations in the core of hot fusion plasmas would permit the detailed investigation of the relationship between turbulence characteristics and variations in global confinement and local gradients. The tangential {CO\${\textbackslash}sb2\$} laser phase contrast imaging system was developed on the Current Drive Experiment Upgrade {(CDX-U),} to allow such measurements to be made. Theoretical work demonstrates that the effect of the plasma on the tangential imaging beam is approximately that of a shift-invariant point-spread function. The result indicates that the recovery of core-localized density fluctuation images using a spatial filter is possible in principle. The imaging process is studied through extensive computer simulations. Results show that a simple step-function phase mirror design provides adequate qualitative image recovery, even in the presence of non-ideal effects in the plasma model, such as a finite \$k{\textbackslash}sb{{\textbackslash}parallel}\$ variation along the field lines and significant field line pitch. The instrumental components of the system are characterized and calibrated and the absolute system sensitivity is calculated. Sound waves are used as test phase objects to calibrate the diagnostic. The tests locate the image plane, verify the system magnification, and demonstrate spatial filtering capabilities. Plasma measurements show adequate signal to noise and k spectrum measurement capability. Localization of the measurement is suggested by measurements of sawtooth modes. Full experimental demonstration of image recovery, however, will require further work. Preliminary analyses of the {MHD} activity and turbulence are done. Analysis of the sawtooth mode measurements indicate a long wavelength structure \$(k{\textbackslash}sb{r}{\textbackslash}leq0.78cm{\textbackslash}sp{-1})\$ localized to the core, and a density fluctuation amplitude of \$(3.7{\textbackslash}pm0.7)cm{\textbackslash}sp{-1},\$ yielding {\${\textbackslash}Delta} n/n{\textbackslash}approx(17{\textbackslash}pm3){\textbackslash}\%.\$ A measurement of the fluctuation k spectrum was also completed, with the finding that most of the fluctuation power lies between \$0.78-2cm{\textbackslash}sp{-1}.\$ Calculation of \$k{\textbackslash}sb{{\textbackslash}perp{\textbackslash}rho{\textbackslash}sb{i}}\$ results in values between 0.21-0.67 which agree with the results of strong electrostatic drift turbulence models.}, file = {lo_tangential_1997.pdf:refs/theses/lo_tangential_1997.pdf:PDF}, keywords = {Fluid {dynamics,Gases,Optics}}, url = {http://proquest.umi.com/pqdweb?did=736586391&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @ARTICLE{loarte_chapter_2007, author = {A. Loarte and B. Lipschultz and {A.S.} Kukushkin and {G.F.} Matthews and {P.C.} Stangeby and N. Asakura and {G.F.} Counsell and G. Federici and A. Kallenbach and K. Krieger and A. Mahdavi and V. Philipps and D. Reiter and J. Roth and J. Strachan and D. Whyte and R. Doerner and T. Eich and W. Fundamenski and A. Herrmann and M. Fenstermacher and P. Ghendrih and M. Groth and A. Kirschner and S. Konoshima and B. {LaBombard} and P. Lang and {A.W.} Leonard and P. {Monier-Garbet} and R. Neu and H. Pacher and B. Pegourie and {R.A.} Pitts and S. Takamura and J. Terry and E. Tsitrone and the {ITPA} Scrape-off Layer and Divertor Physics Topical Group}, title = {Chapter 4: Power and particle control}, journal = {Nuclear Fusion}, year = {2007}, volume = {47}, pages = {S203--S263}, number = {6}, abstract = {Progress, since the {ITER} Physics Basis publication {(ITER} Physics Basis Editors et al 1999 Nucl. Fusion 39 2137-2664), in understanding the processes that will determine the properties of the plasma edge and its interaction with material elements in {ITER} is described. Experimental areas where significant progress has taken place are energy transport in the scrape-off layer {(SOL)} in particular of the anomalous transport scaling, particle transport in the {SOL} that plays a major role in the interaction of diverted plasmas with the main-chamber material elements, edge localized mode {(ELM)} energy deposition on material elements and the transport mechanism for the {ELM} energy from the main plasma to the plasma facing components, the physics of plasma detachment and neutral dynamics including the edge density profile structure and the control of plasma particle content and He removal, the erosion of low- and {high-Z} materials in fusion devices, their transport to the core plasma and their migration at the plasma edge including the formation of mixed materials, the processes determining the size and location of the retention of tritium in fusion devices and methods to remove it and the processes determining the efficiency of the various fuelling methods as well as their development towards the {ITER} requirements. This experimental progress has been accompanied by the development of modelling tools for the physical processes at the edge plasma and plasma-materials interaction and the further validation of these models by comparing their predictions with the new experimental results. Progress in the modelling development and validation has been mostly concentrated in the following areas: refinement in the predictions for {ITER} with plasma edge modelling codes by inclusion of detailed geometrical features of the divertor and the introduction of physical effects, which can play a major role in determining the divertor parameters at the divertor for {ITER} conditions such as hydrogen radiation transport and neutral-neutral collisions, modelling of the ion orbits at the plasma edge, which can play a role in determining power deposition at the divertor target, models for plasma-materials and plasma dynamics interaction during {ELMs} and disruptions, models for the transport of impurities at the plasma edge to describe the core contamination by impurities and the migration of eroded materials at the edge plasma and its associated tritium retention and models for the turbulent processes that determine the anomalous transport of energy and particles across the {SOL.} The implications for the expected performance of the reference regimes in {ITER,} the operation of the {ITER} device and the lifetime of the plasma facing materials are discussed.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/47/6/S04} } @BOOK{lochte-holtgreven_plasma_1995, title = {Plasma Diagnostics}, publisher = {AIP Press}, year = {1995}, author = {W. Lochte-Holtgreven}, pages = {928}, series = {American Vacuum Society classics}, address = {New York}, isbn = {1563963884}, keywords = {High temperature plasmas,Plasma diagnostics}, url = {http://catalog.princeton.edu/cgi-bin/Pwebrecon.cgi?v1=2\&ti=1,2\&Search\_Arg=lochte-holtgreven\&Search\_Code=NAME\_\&CNT=50\&PID=jui-3H2Tfjb0P45lmoUb-HdP5\&SEQ=20080729170858\&SID=1} } @ARTICLE{longmier06, author = {Longmier, B and Baalrud, S and Hershkowitz, N}, title = {Nonambipolar electron source}, journal = {REVIEW OF SCIENTIFIC INSTRUMENTS}, year = {2006}, volume = {77}, pages = {113504}, number = {11}, month = nov, abstract = {A radio frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface has been constructed. All of the random electron flux incident on an exit aperture is extracted through an electron sheath resulting in total nonambipolar flow within the device when the ratio of the ion loss area to the electron loss area is approximately equal to the square root of the ratio of the ion mass to the electron mass, and the ion sheath potential drop at the chamber walls is much larger than T-e/e. The nonambipolar electron source (NES) has an axisymmetric magnetic field of 100 G at the extraction aperture that results in a uniform plasma potential across the aperture, allowing the extraction of all the incident electron flux without the use of grids. A prototype NES has produced 15 A of continuous electron current, using 15 SCCM (SCCM denotes cubic centimeter per minute at STP) Ar, 1200 W rf power at 13.56 MHz, and 6 times gas utilization. Alternatively 8 A of electron current can be produced, using 3 SCCM Ar at 1200 W rf and 20 times gas utilization. NES could replace hollow cathode electron sources in a wide variety of applications.}, doi = {10.1063/1.2393164}, keywords = {cathode}, owner = {egranste}, timestamp = {2007.04.05} } @ARTICLE{zarnstorff88, author = {M. Zarnstorff, et.al.}, title = {Bootstrap current in TFTR}, journal = {Physics Review Letters}, year = {1988}, volume = {60}, pages = {1306}, number = {13}, month = {MAR}, doi = {10.1103/PhysRevLett.60.1306}, keywords = {GPP2, bootstrap current}, owner = {Administrator}, timestamp = {2007.04.07} } @ARTICLE{1963PhRv..129.2403M, author = {{Magnuson}, G.~D. and {Carlston}, C.~E.}, title = {{Electron Ejection from Metals due to 1- to 10-keV Noble Gas Ion Bombardment. I. Polycrystalline Materials}}, journal = {Physical Review }, year = {1963}, volume = {129}, pages = {2403-2408}, month = mar, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1963PhRv..129.2403M}, doi = {10.1103/PhysRev.129.2403}, keywords = {1yr_project} } @ARTICLE{mahdavi_initial_2001, author = {{M.A.} Mahdavi and {M.R.} Wade and {J.G.} Watkins and {C.J.} Lasnier and T. Luce and {S.L.} Allen and {A.W.} Hyatt and C. Baxi and {J.A.} Boedo and {A.S.} Bozek and {N.H.} Brooks and {R.J.} Colchin and {T.E.} Evans and {M.E.} Fenstermacher and {M.E.} Friend and {R.C.} {O'Neill} and {R.C.} Isler and {A.G.} Kellman and {A.W.} Leonard and R. Maingi and {R.A.} Moyer and {T.W.} Petrie and {G.D.} Porter and {M.J.} Schaffer and S. Skinner and {R.D.} Stambaugh and {P.C.} Stangeby and {W.P.} West and {D.G.} Whyte and {N.S.} Wolf}, title = {Initial performance results of the {DIII-D} Divertor 2000}, journal = {Journal of Nuclear Materials}, year = {2001}, volume = {290-293}, pages = {905--909}, month = mar, abstract = {A major upgrade of the {DIII-D} divertor, with the goal of enhancing impurity and density control and increasing the thermal pulse length limit of advanced tokamak {(AT)} plasmas has been successfully completed and commissioned. The integrated system that includes independent cryopumps at both the inner and the outer legs of the divertor, private flux region and outboard baffles, and improved graphite divertor armor, has been successfully applied to a variety of plasma conditions. Comparison of similar discharges before and after the upgrades show that with the new divertor the core plasma neutral source and carbon content are lower by as much as 50\%. Calculations supported by preliminary infra-red {(IR)} camera measurements show that the new graphite armor design increases the limit on the discharge duration, due to temperature of the tile edges reaching sublimation point, by an order of magnitude. With the new system we have been able to control the density of high confinement H-mode plasmas to less than 1/3 of the Greenwald limit. It is observed that with divertor pumping during the current ramp phase the wall particle inventory and consequently the density rise after the H-mode transition can be significantly reduced.}, doi = {{10.1016/S0022-3115(00)00500-6}}, issn = {0022-3115}, keywords = {{DIII-D,} Divertor}, url = {http://www.sciencedirect.com/science/article/B6TXN-42K5JDD-77/2/ea6fb58d217505569a1d7695f64a7d5c} } @ARTICLE{majeski_performance_2009, author = {R. Majeski and L. Berzak and T. Gray and R. Kaita and T. Kozub and F. Levinton and {D.P.} Lundberg and J. Manickam and {G.V.} Pereverzev and K. Snieckus and V. Soukhanovskii and J. Spaleta and D. Stotler and T. Strickler and J. Timberlake and J. Yoo and L. Zakharov}, title = {Performance projections for the lithium tokamak experiment {(LTX)}}, journal = {Nuclear Fusion}, year = {2009}, volume = {49}, pages = {055014}, number = {5}, note = {Comparisons of CDX-U with scaling laws are useless, because recyling is the major feature, which does not enter into any existing confinement scaling laws. Major factor determining variation in ITER98P(y,1) scaling is the power input, since the loop voltage drops (due to higher Te) with low-R. CDX-U operated in low-collisionality regime: $\nu_{i,e}^* < 0.1$. Ion-electron equilibration time was 5-8 ms for high-R to 15-20ms for low-R, so charge-exchange not dominant energy loss mechanism. Radiated power was significantly less than the Ohmic input power. ASTRA runs using RTM assumed R=0, and neoclassical. Addition of GLF23 to model anomalous transport didn't produce any real change because there was no significant Te gradient. Ion temperature not well reproduced by RTM; experimentally measured doppler broadening of C IV line gave Ti about 70-80 eV, but deuterium ion temperature expected to be even higher. Model predicted Ti about 20-30. Model predicts LTX will have $\tau_E \sim 25$ms in Ohmic operation, with $T_e \sim 1.5$ keV. Will pulse off gas sources to transiently remove the neutral gas load from the edge, bringing $\tau_E \sim 30$ms.}, abstract = {Use of a large-area liquid lithium limiter in the {CDX-U} tokamak produced the largest relative increase (an enhancement factor of 5-10) in Ohmic tokamak confinement ever observed. The confinement results from {CDX-U} do not agree with existing scaling laws, and cannot easily be projected to the new lithium tokamak experiment {(LTX).} Numerical simulations of {CDX-U} low recycling discharges have now been performed with the {ASTRA-ESC} code with a special reference transport model suitable for a diffusion-based confinement regime, incorporating boundary conditions for nonrecycling walls, with fuelling via edge gas puffing. This model has been successful at reproducing the experimental values of the energy confinement (4-6 ms), loop voltage ({\textless}0.5 V), and density for a typical {CDX-U} lithium discharge. The same transport model has also been used to project the performance of the {LTX,} in Ohmic operation, or with modest neutral beam injection {(NBI).} {NBI} in {LTX,} with a low recycling wall of liquid lithium, is predicted to result in core electron and ion temperatures of 1-2 {keV,} and energy confinement times in excess of 50 ms. Finally, the unique design features of {LTX} are summarized.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/49/5/055014} } @ARTICLE{majeski_plasma_2003, author = {R. Majeski and M. Boaz and D. Hoffman and B. Jones and R. Kaita and H. Kugel and T. Munsat and J. Spaleta and V. Soukhanovskii and J. Timberlake and L. Zakharov and G. Antar and R. Doerner and S. Luckhardt and R. W. Conn and M. Finkenthal and D. Stutman and R. Maingi and M. Ulrickson}, title = {Plasma performance improvements with liquid lithium limiters in {CDX-U}}, journal = {Fusion Engineering and Design}, year = {2003}, volume = {65}, pages = {443--447}, number = {3}, month = apr, abstract = {The use of flowing liquid lithium as a first wall for a reactor has potentially attractive physics and engineering features. The current drive experiment-upgrade {(CDX-U)} at the Princeton Plasma Physics Laboratory has begun experiments with a fully toroidal liquid lithium limiter. {CDX-U} is a compact {(R=34} cm, a=22 cm, Btoroidal=2 {kG,} {IP=100} {kA,} Te(0){\textasciitilde}100 {eV,} ne(0){\textasciitilde}5×1019 m-3) short-pulse ({\textless}25 ms) spherical tokamak with extensive diagnostics. The limiter, which consists of a shallow circular stainless steel tray of radius 34 cm and width 10 cm, can be filled with lithium to a depth of a few millimeters, and forms the lower limiting surface for the discharge. Heating elements beneath the tray are used to liquefy the lithium prior to the experiment. The total area of the tray is approximately 2000 cm2. The tokamak edge plasma, when operated in contact with the lithium-filled tray, shows evidence of reduced impurities and recycling. The reduction in recycling and impurities is largest when the lithium is liquefied by heating to 250 {°C.} Discharges which are limited by the liquid lithium tray show evidence of performance enhancement. Radiated power is reduced and there is spectroscopic evidence for increases in the core electron temperature. Furthermore, the use of a liquid lithium limiter reduces the need for conditioning discharges prior to high current operation. The future development path for liquid lithium limiter systems in {CDX-U} is also discussed.}, doi = {10.1016/S0920-3796(03)00016-4}, issn = {0920-3796}, keywords = {{Limiter,Lithium,Tokamak}}, url = {http://www.sciencedirect.com/science/article/B6V3C-47X21DP-2/2/a8a6dddc6b54f96dfa69672ab2e9734b} } @ARTICLE{majeski2006, author = {R. Majeski and R. Doerner and T. Gray and R. Kaita and R. Maingi and D. Mansfield and J. Spaleta and V. Soukhanovskii and J. Timberlake and L. Zakharov}, title = {Enhanced Energy Confinement and Performance in a Low-Recycling Tokamak}, journal = {Physical Review Letters}, year = {2006}, volume = {97}, pages = {075002}, number = {7}, eid = {075002}, note = {Recyling in 50--60% range presented, but were able to get as low as 30% using compact Li rail limiter, partial solid Li coatings (up to 1000 A thick) on SS vessel wall. Liquid Li used to ensure that D does not ``load'' the surface since it is highly diffusive ($ \gt 10^4 \textrm{cm^2/s}$ at 300-400$\textrm{^\circ C}$) to prevent saturation of the surface. The Li coatings were deposited rapidly (by evaporating Li and monitoring with a quartz microbalance) and discharge innitiated right after ($\lt$ 1 min). Relative $D_\alpha$ radiation at the center stack, which is the primary contact point was used to measure recycling. Triple probe at last closed flux surf. measure density and $T_e$ (30 eV with Li and 20 eV without). Strong gas fueling was necessary with Li to keep plasma density. Eff. particle confinement time estimated by measuring the density decay when fueling terminated (2--3 ms with Li). Gives eqn. for energy confinement time in terms of plasma KE, rate of change in edge poloidal flux, and time deriv. of plasma KE and magnetic energy. Diamagnetic loop and EQU reconstruction give stored plasma KE and poloidal flux, rogowski coil gives the plasma current. Two estimates of $\tau_E$ given, when derivatives of magnetic energy and KE are zero respectively to give an error estimate. Introducing Li gives a factor of 6+ improvement and loop voltage is reduced by a factor of 4 (from 2--3 V to 0.5 V). Carbon IV impurity temp. is increased from 24 to 71 eV, and amplitude reduced by a factor of 10.}, doi = {10.1103/PhysRevLett.97.075002}, keywords = {lithium, plasma facing components, recycling}, numpages = {4}, publisher = {APS}, url = {http://link.aps.org/abstract/PRL/v97/e075002} } @ARTICLE{majeski_testing_2004, author = {R. Majeski and R. Kaita and M. Boaz and P. Efthimion and T. Gray and B. Jones and D. Hoffman and H. Kugel and J. Menard and T. Munsat and A. {Post-Zwicker} and J. Spaleta and G. Taylor and J. Timberlake and R. Woolley and L. Zakharov and M. Finkenthal and D. Stutman and G. Antar and R. Doerner and S. Luckhardt and R. Seraydarian and R. Maingi and M. Maiorano and S. Smith and D. Rodgers and V. Soukhanovskii}, title = {Testing of liquid lithium limiters in {CDX-U}}, journal = {Fusion Engineering and Design}, year = {2004}, volume = {72}, pages = {121--132}, number = {1-3}, month = nov, abstract = {Part of the development of liquid metals as a first wall or divertor for reactor applications must involve the investigation of plasma-liquid metal interactions in a functioning tokamak. Most of the interest in liquid metal walls has focused on lithium. Experiments with lithium limiters have now been conducted in the Current Drive {Experiment-Upgrade} {(CDX-U)} device at the Princeton Plasma Physics Laboratory. Initial experiments used a liquid lithium rail limiter {(L3)} built by the University of California at San Diego. Spectroscopic measurements showed some reduction of impurities in {CDX-U} plasmas with the L3, compared to discharges with a boron carbide limiter. While no reduction in recycling was observed with the L3, which had a plasma-wet area of approximately 40 cm2, subsequent experiments with a larger area fully toroidal lithium limiter demonstrated significant reductions in both recycling and in impurity levels. Two series of experiments with the toroidal limiter have now been performed. In each series, the area of exposed, clean lithium was increased, until in the latest experiments, the liquid lithium plasma-facing area was increased to 2000 cm2. Under these conditions, the reduction in recycling required a factor of eight increase in gas fueling in order to maintain the plasma density. The loop voltage required to sustain the plasma current was reduced from 2 V to 0.5 V. This paper summarizes the technical preparations for lithium experiments and the conditioning required to prepare the lithium surface for plasma operations. The mechanical response of the liquid metal to induced currents, especially through contact with the plasma, is discussed. The effect of the lithium-filled toroidal limiter on plasma performance is also briefly described.}, doi = {10.1016/j.fusengdes.2004.07.002}, issn = {0920-3796}, keywords = {{CDX-U,Liquid} lithium {limiters,Plasma-edge} interactions}, url = {http://www.sciencedirect.com/science/article/B6V3C-4D8MP2P-1/2/5ad867db64a09ab785e85d489796a921} } @ARTICLE{ltxaps2006, author = {{Majeski}, R. and {Gray}, T. and {Kaita}, R. and {Kozub}, T. and {Spaleta}, J. and {Timberlake}, J. and {Zakharov}, L. and {Soukhanovskii}, V. and {Maingi}, R. and {Krasheninnikov}, S.}, title = {{Status of the Lithium Tokamak eXperiment (LTX)}}, journal = {APS Meeting Abstracts}, year = {2006}, pages = {1012P-+}, month = oct, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2006APS..DPPVP1012M}, keywords = {lithium, plasma facing components, recycling} } @ARTICLE{malkin_fast_1999, author = {V. M. Malkin and G. Shvets and N. J. Fisch}, title = {Fast Compression of Laser Beams to Highly Overcritical Powers}, journal = {Physical Review Letters}, year = {1999}, volume = {82}, pages = {4448}, month = may, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, url = {http://link.aps.org/abstract/PRL/v82/p4448} } @ARTICLE{manini_signal_2003, author = {A. Manini and {J.-M.} Moret and F. Ryter and the {ASDEX} Upgrade Team}, title = {Signal processing techniques based on singular value decomposition applied to modulated {ECH} experiments}, journal = {Nuclear Fusion}, year = {2003}, volume = {43}, pages = {490--511}, number = {6}, abstract = {The analysis and interpretation of perturbative modulated electron cyclotron heating {(MECH)} discharges for power deposition localization using different diagnostics, such as electron cyclotron emission {(ECE)} and soft x-ray {(SXR)} measurements, are presented. In particular, the experimental determination of the {MECH} power deposition is investigated, which is a fundamental requirement, for example, for heat transport studies. The most important problem is related to the coupling between the {MECH} and the sawtooth activity of the plasma, which disturbs both {ECE} and {SXR} measurements. Several techniques have been adopted to circumvent this difficulty. In particular, the singular value decomposition {(SVD)} and the generalized singular value decomposition {(GSVD)} have been tested. However, both methods are incapable of treating the problem correctly, which leads to potential misinterpretation of the results. A new method based on system identification using the {SVD} {(SI-SVD)} is developed and applied. This method, within reasonable limits induced by the assumption of linearity, is capable of simultaneously separating the {MECH} from the sawtooth contributions to both {ECE} electron temperature measurements and {SXR} emission measurements. Such a method is in particular applied to a neutral beam injection {(NBI)} heated {ASDEX} Upgrade discharge in which {MECH} is added in order to analyse electron heat transport in a mostly ion-heated plasma. Since the {NBI} heating is also partly modulated with short pulses which coincide with the sawtooth crashes to improve their stability, both the {MECH} and the {NBI} deposition profiles are determined. Moreover, treating the signals with the {SI-SVD} procedure enables a study of the plasma dynamic response also at higher {MECH} harmonic numbers.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/43/6/312} } @INPROCEEDINGS{manzella_ht-characterization_1995, author = {Manzella, D. H. and M. Sankovic}, title = {Hall Thruster Ion Beam Characterization}, booktitle = {31st AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit}, year = {1995}, series = {AIAA paper no. 1995-2927}, address = {San Diego, CA}, month = {JUL}, owner = {erikg}, timestamp = {2008.04.01}, url = {http://www.aiaa.org/content.cfm?pageid=413} } @ARTICLE{marinoni_design_2006, author = {A. Marinoni and S. Coda and R. Chavan and G. Pochon}, title = {Design of a tangential phase contrast imaging diagnostic for the {TCV} tokamak}, journal = {Rev. Sci. Instrum.}, year = {2006}, volume = {77}, pages = {10E929--4}, month = oct, doi = {10.1063/1.2222333}, keywords = {plasma density,plasma diagnostics,plasma fluctuations,plasma instability,plasma light propagation,plasma radiofrequency heating,plasma temperature,plasma toroidal confinement,plasma transport {processes,Tokamak} devices}, url = {http://link.aip.org/link/?RSI/77/10E929/1} } @ARTICLE{sanchez_sep-overview_1998, author = {Mart\'inez-S\'anchez, M. and Pollard, J.~E.}, title = {Spacecraft Electric Propulsion -- An Overview}, journal = {Journal of Propulsion and Power}, year = {1998}, volume = {14}, pages = {688-699}, number = {5}, keywords = {electric propulsion, review, 1yr_project}, owner = {egranste}, timestamp = {2007.05.16} } @ARTICLE{mazzucato_short-scale_2008, author = {E. Mazzucato and D. R. Smith and R. E. Bell and S. M. Kaye and J. C. Hosea and B. P. LeBlanc and J. R. Wilson and P. M. Ryan and C. W. Domier and Jr. Luhmann and H. Yuh and W. Lee and H. Park}, title = {Short-Scale Turbulent Fluctuations Driven by the Electron-Temperature Gradient in the National Spherical Torus Experiment}, journal = {Physical Review Letters}, year = {2008}, volume = {101}, pages = {075001-4}, doi = {10.1103/PhysRevLett.101.075001}, url = {http://link.aps.org/abstract/PRL/v101/e075001} } @ARTICLE{2002PhRvE..66c6401M, author = {Meezan, N.~B. and Cappelli, M.~A.}, title = {{Kinetic study of wall collisions in a coaxial Hall discharge}}, journal = {\pre}, year = {2002}, volume = {66}, pages = {036401-+}, number = {3}, month = sep, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2002PhRvE..66c6401M}, doi = {10.1103/PhysRevE.66.036401}, keywords = {Hall thruster, collisions, 1yr_project} } @ARTICLE{2001PhRvE..63b6410M, author = {{Meezan}, N.~B. and {Hargus}, W.~A. and {Cappelli}, M.~A.}, title = {{Anomalous electron mobility in a coaxial Hall discharge plasma}}, journal = {\pre}, year = {2001}, volume = {63}, pages = {026410-+}, number = {2}, month = feb, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2001PhRvE..63b6410M}, doi = {10.1103/PhysRevE.63.026410}, keywords = {anomalous diffusion, Hall thrusters, 1r_project} } @PHDTHESIS{menard_high-harmonic_1998, author = {Jonathan Edward Menard}, title = {High-harmonic fast wave coupling and heating experiments in the CDX-U spherical tokamak}, school = {Princeton University}, year = {1998}, note = {Ph.D.}, keywords = {HHFW,High Harmonic Fast Wave,microwave scattering,RF heating}, url = {http://proquest.umi.com/pqdweb?did=738029661\&Fmt=7\&clientId=17210\&RQT=309\&VName=PQD} } @ARTICLE{menard_internal_2005, author = {{J.E.} Menard and {R.E.} Bell and {E.D.} Fredrickson and {D.A.} Gates and {S.M.} Kaye and {B.P.} {LeBlanc} and R. Maingi and {S.S.} Medley and W. Park and {S.A.} Sabbagh and A. Sontag and D. Stutman and K. Tritz and W. Zhu and the NSTX Research Team}, title = {Internal kink mode dynamics in high-β {NSTX} plasmas}, journal = {Nuclear Fusion}, year = {2005}, volume = {45}, pages = {539--556}, number = {7}, abstract = {Saturated internal kink modes have been observed in many of the highest toroidal b discharges of the National Spherical Torus Experiment (NSTX). These modes often cause rotation flattening in the plasma core, can degrade fast-ion confinement and in some cases contribute to the complete loss of plasma angular momentum and stored energy. Characteristics of the modes are measured using soft x-ray, kinetic profile and magnetic diagnostics. Toroidal flows approaching Alfvenic speeds, island pressure peaking and enhanced viscous and diamagnetic effects associated with high-b may contribute to mode nonlinear stabilization. These saturation mechanisms are investigated for NSTX parameters and compared with experimental data.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/45/7/001/} } @ARTICLE{michael_upgraded_2006, author = {C. A. Michael and K. Tanaka and L. Vyacheslavov and A. Sanin and K. Kawahata and S. Okajima}, title = {Upgraded two-dimensional phase contrast imaging system for fluctuation profile measurement on {LHD}}, journal = {Rev. Sci. Instrum.}, year = {2006}, volume = {77}, pages = {10E923--5}, month = oct, doi = {10.1063/1.2336468}, keywords = {plasma boundary layers,plasma density,plasma diagnostics,plasma fluctuations,plasma toroidal confinement,plasma turbulence,stellarators}, url = {http://link.aip.org/link/?RSI/77/10E923/1} } @ARTICLE{michael_2d_pci_2007, author = {Clive Michael and Kenji Tanaka and Leonid Vyacheslavov and Andrei Sanin and Kazuo Kawahata and S. Okajima}, title = {Interpretation of Line-Integrated Signals from 2-D Phase Contrast Imaging on LHD}, journal = {Plasma and Fusion Research}, year = {2007}, volume = {2}, pages = {S1034-S1034}, doi = {10.1585/pfr.2.S1034}, keywords = {phase contrast imaging, pci, maximum entropy, correlation, turbulence, line-integration}, owner = {erikg}, timestamp = {2009.04.22}, url = {http://www.jstage.jst.go.jp/article/pfr/2/0/2_S1034/_article} } @ARTICLE{mikellides05, author = {Mikellides, IG and Katz, I and Goebel, DM and Polk, JE}, title = {Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region}, journal = {Journal of Applied Physics}, year = {2005}, volume = {98}, pages = {113303}, number = {11}, month = dec, note = {Detail of this model is motivated to quantify the effects of the plasma on emitter and keeper lifetime; suggest that anomalous heating of the plasma is possible near the orifice region. Particle and heat fluxes to the emitter ealls, E-field distribution to understand how ions are expelled out of the cathode must be understood. Electron density follows a nonmonotonc variation along the axis of symmetry, possibly associated with the large open area of the orifice. Method: 2D fluid, mesh, ``zero-sheath'' boundary conditions, Schottky-enhanced emission from emitter surface, electrons emitted from the insert are attracted by a positively-biased keeper electrode downstream; classical collisions are dominant in determining transport (highly collisional). Assumes quasi-neutral, single ionization, does not seem to incorporate bulk recombination (maybe recomb. at surface dominates), neglects inertia, viscosity and the ``thermoelectric force'' due to gradients in the temperature of the species. Thus, this model can't capture high-freq. phenomena. Plasma is optically thick to radiation from Xenon excitation, so most of the radiation is trapped in the plasma. Scalar quantities are cell-centered, fluxes are edge-centered. Flux and Dirichlet BCs are used; sheaths are too thin to be captured by model and is assumed to be a perfect thermal insulator; cathode walls are at ground relative to the plasma, zero electron emission is assumed from the orifica plate and conducting wall. Long-term conditioning of the emitter might explain the decreasing disch. voltage after hours of operation. Theory and experiment show that far upstream, mass and heat transport are classical, but closer to the orifice, potential and e temp. are too high for classical collisions; hence, they propose anomalous heating as a result of 2-stream instabilities. The Buneman instability and others (p. 9) may also play a part. Resonant charge-exchange collisions betw. fast ions and slow neutrals may lead o gas temps. above 2000K. Turbulent heating may occur due to wave growth from stramng electrons and ions, subject to reduced Landau damping due to the low ion-electron temperature ratio.}, abstract = {Despite their long history and wide range of applicability that includes electric propulsion, detailed understanding of the driving physics inside orificed hollow cathodes remains elusive. The theoretical complexity associated with the multicomponent fluid inside the cathode, and the difficulty of accessing empirically this region, have limited our ability to design cathodes that perform better and last longer. A two-dimensional axisymmetric theoretical model of the multispecies fluid inside an orificed hollow cathode is presented. The level of detail attained by the model is allowed by its extended system of governing equations not solved for in the past within the hollow cathode. Such detail is motivated in part by the need to quantify the effect(s) of the plasma on the emitter life, and by the need to build the foundation for future modeling that will assess erosion of the keeper plate. Results from numerical simulations of a 1.2-cm-diam cathode operating at a discharge current of 25 A and a gas flow rate of 5 SCCM show that approximately 10 A of electron current, and 3.45 A of ion current return back to the emitter surface. The total emitted electron current is 33.8 A and the peak emitter temperature is found to be 1440 K. Comparisons with the measurements suggest that anomalous heating of the plasma is possible near the orifice region. The model predicts heavy species temperatures as high as 2034 K and peak voltage drops near the emitting surface not exceeding 8 V. (c) 2005 American Institute of Physics.}, doi = {10.1063/1.2135409}, keywords = {hollow cathode, 1yr_project}, owner = {egranste}, timestamp = {2007.04.19} } @ARTICLE{mikellides07, author = {Ioannis G. Mikellides and Ira Katz and Dan M. Goebel and Kristina K. Jameson}, title = {Evidence of nonclassical plasma transport in hollow cathodes for electric propulsion}, journal = {Journal of Applied Physics}, year = {2007}, volume = {101}, pages = {063301}, month = mar, note = {Hollow cathodes use porous W inserts similar to the dispenser cathode technologies in microwave tubes. Molybdenum tube, W-Th orifice plate, and barium-impregnated W insert, graphite keeper electrode. Emissive probe used for $V_p$ oscillation (up to 1 MHz) measurements. Most oscillations between 50--500kHz: few orders of mag. less than $\omega_{pi}$ indicating ion-acoustic source. Erosion of the keeper cathode limits the lifetime, so work has focused on measuring high-energy ions and identifying mechanisms that created them. 2D structure of $V_p$ may indicate attainable ion energies, but why discharge establishes rising $V_p$, sometimes fluctuations, sometimes nonmonotonic is not known. Heating mechanisms (1-2 eV electrons inside to 5 eV outside) not understood. Anomalous transport is necessary to explain the high temperatures and steep potential gradients, also classical transport and Ohm's law predict high ($> 4 c_s$) relative electon-ion drift speeds which would normally lead ot violent streaming instabilities (which would disrupt the discharge), but are not observed. Postulates that these instabilities quench into a low-freq. turbulent mode (ion-acoustic turbulence?) that anomalously heats the electrons. HIghest relative drifts and largest-amplitude $V_p$ oscillations occur along keeper surface facing the anode. Deviations from Maxwellian EEDF, effect of hot-ion tail not known. This article just shows that much higher level of resistivity necessary to explain macroscopic measurements. They assume quasineutral and singly-charged ions. Electron momentum equation (dropping electron inertia, ion contribution, B field) shows that resistive electric field tries to increase $V_p$, while pressure gradient force drives a negative $V_p$ gradient. Analytic estimates bound measured resistivity between 3-50 times classical: this bounding performed by bounding the electron current density along the axis on two extremes, all other params were directly measured. Simulation uses 2-fluid plasma and neutral gas, goal is to determine time-averaged quantities, not dynamic soln. Assume that any waves are quenched to low-freq. turbulence to enhance effective charged-particle collision cross-section. $\lambda_{mfp} \sim T_s^2$ so cold ions can have shorter $\lambda_{mfp}$ than hot electrons. $\lambda_{mfp} \ll L$ so seek steady-state, transport-dominated solutions (ie. drop inertia terms). Single energy eqn used for heavy species (since comparable mass). These simulations give upper bound on the effect of turb, because turbulence would decrease ion-electron equilibration time and ions would need their own energy equation. Simulations also assume that $n$ is uniform along anode boundary, which is specified according to measurement. Inside the orfice and keeper region neutrals are rarefied, need PIC or direct Monte-Carlo siumation of particles; here assumed gas particles in rarefied regions expand freely in straight-line trajectories from a preset boundary. Waves and collisionless can lead to runaway electrons, but turbulent waves and slight deviations from Maxwellian EEDF can allow electron-wave effects to be modeled by appropriate forms of $\nu_{e,coll}$ based on turbulence spectra. (Ref 15) They consider only current-driven, 2 stram instability. Shows stability diagram for Buneman and ion-acoustic unstable. Incorporates Stringer's formalism that effective $\nu$ scales with linear growth rate, and Sagdeev's anomalous freq. that incorporates estimate of nonlinear saturation (higher prediction).}, abstract = {Measurements, simplified analyses, and two-dimensional numerical simulations with a fluid plasma model show that classical resistivity cannot account for the elevated electron temperatures and steep plasma potential gradients measured in a 2527.5 A electric propulsion hollow cathode. The cathode consisted of a 1.5 cm hollow tube with an ~0.28 cm diameter orifice and was operated with 5.5 SCCM (SCCM denotes cubic centimeter per minute at STP) of xenon flow using two different anode geometries: a segmented cone and a circular flat plate. The numerical simulations show that classical resistivity yields as much as four times colder electron temperatures compared to the measured values in the orifice and near-plume regions of the cathode. Classical transport and Ohm's law also predict exceedingly high electron-ion relative drift speeds compared to the electron thermal speed (>4). It is found that the addition of anomalous resistivity based on existing growth rate formulas for electron-ion streaming instabilities improves qualitatively the comparison between the numerical results and the time-averaged measurements. Simplified analyses that have been based largely on the axial measurements support the conclusion that additional resistivity is required in Ohm's law to explain the measurements. The combined results from the two-dimensional simulations and the analyses bound the range of enhanced resistivity to be 3100 times the classical value.}, file = {\\Docs\\general papers\\mikellides07.pdf:\\Docs\\general papers\\mikellides07.pdf:PDF}, keywords = {hollow cathode discharge, 1yr_project}, owner = {egranste}, timestamp = {2007.03.26}, url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JAPIAU000101000006063301000001&idtype=cvips&gifs=yes} } @BOOK{mikhailovskiplasmainstabilities, title = {Studies in Soviet Science: Theory of Plasma Instabilities}, year = {1974}, author = {A.B. Mikhailovski}, volume = {2}, keywords = {GPP2, collisional drift waves}, owner = {erikg}, timestamp = {2007.05.09} } @ARTICLE{miller_xenon_2002, author = {J. Scott Miller and Steve H. Pullins and Dale J. Levandier and Yu-hui Chiu and Rainer A. Dressler}, title = {Xenon charge exchange cross sections for electrostatic thruster models}, journal = {Journal of Applied Physics}, year = {2002}, volume = {91}, pages = {984-991}, number = {3}, month = feb, doi = {10.1063/1.1426246}, keywords = {atom-ion collisions; charge exchange; xenon; positive ions; ion engines; 1yr_project}, url = {http://link.aip.org/link/?JAP/91/984/1} } @ARTICLE{miller_noncircular_1998, author = {R. L. Miller and M. S. Chu and J. M. Greene and Y. R. {Lin-Liu} and R. E. Waltz}, title = {Noncircular, finite aspect ratio, local equilibrium model}, journal = {Physics of Plasmas}, year = {1998}, volume = {5}, pages = {973--978}, number = {4}, month = apr, doi = {10.1063/1.872666}, keywords = {{ASPECT} {RATIO,BALLOONING} {INSTABILITY,KINETICS,MHD} {EQUILIBRIUM,plasma} kinetic theory,plasma toroidal {confinement,TOKAMAK} {DEVICES}}, url = {http://link.aip.org/link/?PHP/5/973/1} } @ARTICLE{minagami82, author = {S. Minami and S. Tsutsumi and Y. Takeya}, title = {Graphical Analysis method for a retarding potential analyzer and its application to the real-time measurements of ion temperature in space plasmas}, journal = {Review of Scientific Instruments}, year = {1982}, volume = {53}, pages = {1709-1713}, number = {11}, month = nov, file = {Docs\\Diagnostics\\Retarding Potential Analyzer\\minagami82.pdf:Docs\\Diagnostics\\Retarding Potential Analyzer\\minagami82.pdf:PDF}, keywords = {retarding potential analyzer, RPA, 1yr_project}, owner = {egranste}, timestamp = {2007.03.07} } @ARTICLE{mizuguchi_dynamics_2000, author = {Naoki Mizuguchi and Takaya Hayashi and Tetsuya Sato}, title = {Dynamics of spherical tokamak plasma on the internal reconnection event}, journal = {Physics of Plasmas}, year = {2000}, volume = {7}, pages = {940-949}, month = mar, doi = {10.1063/1.873892}, keywords = {internal reconnection event,plasma instability,plasma magnetohydrodynamics,plasma nonlinear processes,plasma simulation,plasma toroidal confinement,spherical torus}, url = {http://link.aip.org/link/?PHP/7/940/1} } @INPROCEEDINGS{moeller_mhd_hveps_power_demonstration_2008, author = {T. Moeller AND John Lineberry AND L.L. Begg AND Ron Litchfor AND Robert Rhodes}, title = {HVEPS Combustion Driven MHD Power Demonstration Tests}, booktitle = {39th Plasmadynamics and Lasers Conference}, year = {2008}, series = {AIAA-2008-4097}, owner = {erikg}, timestamp = {2009.09.30}, url = {http://www.aiaa.org/content.cfm?pageid=406} } @ARTICLE{mora03, author = {P. Mora}, title = {Plasma Expansion into a Vacuum}, journal = {Physical Review Letters}, year = {2003}, volume = {90}, pages = {185002}, number = {18}, month = may, keywords = {charge separation, plasma expansion, 1yr_project}, owner = {egranste}, timestamp = {2007.04.13} } @ARTICLE{mora79, author = {{Mora}, P. and {Pellat}, R.}, title = {{Self-similar expansion of a plasma into a vacuum}}, journal = {Physics of Fluids}, year = {1979}, volume = {22}, pages = {2300-2304}, month = dec, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1979PhFl...22.2300M&db_key=PHY}, keywords = {plasma expansion, 1yr_project} } @ARTICLE{morris_neoclassical_1996, author = {R. C. Morris and M. G. Haines and R. J. Hastie}, title = {The neoclassical theory of poloidal flow damping in a tokamak}, journal = {Physics of Plasmas}, year = {1996}, volume = {3}, pages = {4513-4520}, month = dec, keywords = {BANANA REGIME,DAMPING,DISTRIBUTION FUNCTIONS,KINETIC EQUATIONS,NEOCLASSICAL TRANSPORT THEORY,PLASMA DRIFT,TOKAMAK DEVICES}, url = {http://link.aip.org/link/?PHP/3/4513/1} } @ARTICLE{mueck_demonstration_2007, author = {A. Mueck and L. Curchod and Y. Camenen and S. Coda and T. P. Goodman and H. P. Laqua and A. Pochelon and L. Porte and F. Volpe}, title = {Demonstration of {Electron-Bernstein-Wave} Heating in a Tokamak via {O-X-B} {Double-Mode} Conversion}, journal = {Physical Review Letters}, year = {2007}, volume = {98}, pages = {175004--4}, number = {17}, month = apr, doi = {{10.1103/PhysRevLett.98.175004}}, url = {http://link.aps.org/abstract/PRL/v98/e175004} } @ARTICLE{munsat_transient_2002, author = {T. Munsat and P. C. Efthimion and B. Jones and R. Kaita and R. Majeski and D. Stutman and G. Taylor}, title = {Transient transport experiments in the current-drive experiment upgrade spherical torus}, journal = {Physics of Plasmas}, year = {2002}, volume = {9}, pages = {480--487}, number = {2}, month = feb, doi = {10.1063/1.1428557}, keywords = {plasma diagnostics, plasma toroidal confinement, plasma transport processes, sawtooth instability}, url = {http://link.aip.org/link/?PHP/9/480/1} } @PHDTHESIS{munsat_transient_2001, author = {Tobin Leo Munsat}, title = {Transient transport experiments in the {CDX-U} spherical torus}, school = {Princeton University}, year = {2001}, note = {{Ph.D.}}, comment = {Electron transport has been measured in {CDX-U} using two separate perturbative techniques. Gas modulation at the plasma edge introduces cold-pulses which propagate towards the plasma center, providing time-of-flight information leading to a determination of Ç e as a function of radius. Sawteeth at the q = 1 radius (r/a ∼ 0.15) induce heat-pulses which propagate outward towards the plasma edge, providing a complementary time-of-flight based Ç e profile measurement. This work represents the first localized measurement of Ç e in a spherical torus. It is found that Ç e = 1-2 m 2 /s in the plasma core (r/a {\textless} 1/3), increasing by an order of magnitude or more outside of this region. Furthermore, the Ç e profile exhibits a sharp transition near r/a = 1/3, indicating a possible transport barrier. Spectral and profile analyses of the soft x-ray, scanning interferometer, and edge probe data show no evidence of a significant magnetic island in the high Ç e region. In support of the electron transport experiments, a multichannel Thomson scattering system has been designed and constructed, providing the first electron profile information in {CDX-U.} The edge cold-pulse experiments make extensive use of the {EBW} electron temperature diagnostic, the sawtooth heat-pulse measurements are made with the soft x-ray array, and Ç e profiles are compared with T e and n e profiles from the Thomson scattering system.}, keywords = {Fluid {dynamics,Gases}}, url = {http://proquest.umi.com/pqdweb?did=727876261&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @ARTICLE{mynick_transport_2006, author = {H. E. Mynick}, title = {Transport optimization in stellarators}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {058102-7}, month = may, keywords = {plasma toroidal confinement,plasma transport processes,stellarators}, url = {http://link.aip.org/link/?PHP/13/058102/1} } @ARTICLE{najmabadi_spherical_2003, author = {F. Najmabadi}, title = {Spherical torus concept as power plants--the {ARIES-ST} study}, journal = {Fusion Engineering and Design}, year = {2003}, volume = {65}, pages = {143--164}, number = {2}, month = feb, abstract = {Recent experimental achievements and theoretical studies have generated substantial interest in the spherical torus concept. The {ARIES-ST} study was undertaken as a national {US} effort to investigate the potential of the spherical tokamak concept as a fusion power plant. This 1000 {MWe} fusion power plant conceptual design has an aspect ratio of 1.6, a major radius of 3.2 m, a plasma elongation (at 95\% flux surface) of 3.4 and triangularity of 0.64. This configuration attains a plasma {[beta]T} of 50\% (which is 90\% of theoretical limit). While the plasma current is 28 {MA,} the almost perfect alignment of bootstrap and equilibrium current density profiles results in a current-drive power of only 28 {MW.} The on-axis toroidal field of 2.1 T and the peak field at the {TF} coil of 7.4 T led to 329 {MW} of Joule losses in the normal-conducting {TF} system. The power core uses an advanced [`]dual-cooled' breeding blanket with flowing {PbLi} breeder and He-cooled ferritic steel structures that can achieve a thermal conversion efficiency of {\textasciitilde}45\%. The {ARIES-ST} study has highlighted many areas where trade-off among physics and engineering systems are critical in determining the optimum regime of operation for {ST} power plants.}, doi = {{10.1016/S0920-3796(02)00302-2}}, issn = {0920-3796}, keywords = {Fusion power {plants,Spherical} {tokamark,Spherical} torus}, url = {http://www.sciencedirect.com/science/article/B6V3C-47NF896-3/2/32ebb2fe91eb4268bd1d0de8222e5fbf} } @ARTICLE{najmabadi_collisional_1984, author = { F NAJMABADI and RW CONN and RH COHEN}, title = {COLLISIONAL END LOSS OF ELECTROSTATICALLY CONFINED PARTICLES IN A MAGNETIC-MIRROR FIELD}, journal = {NUCLEAR FUSION}, year = {1984}, volume = {24}, pages = {75-84}, issn = {0029-5515} } @PHDTHESIS{nazikian_interferometric_1989, author = {Raffi Nazikian}, title = {Interferometric Study of Density Fluctuations in a Tokamakplasma}, school = {Australian National University}, year = {1989}, note = {{Ph.D.}}, keywords = {{fluctuations,Interferometry,optical} {diagnostics,Plasma} {density,Tokamaks}}, pages = {1} } @ARTICLE{nazikian_tutorial_2001, author = {R. Nazikian and G. J. Kramer and E. Valeo}, title = {A tutorial on the basic principles of microwave reflectometry applied to fluctuation measurements in fusion plasmas}, journal = {The 42nd annual meeting of the division of plasma physics of the American Physical Society and the 10th international congress on plasma physics}, year = {2001}, volume = {8}, pages = {1840-1855}, month = may, doi = {10.1063/1.1362534 }, keywords = {fusion reactor instrumentation,geometrical optics,microwave reflectometry,plasma density,plasma diagnostics,plasma fluctuations,plasma magnetohydrodynamics,plasma turbulence,Tokamak devices}, url = {http://link.aip.org/link/?PHP/8/1840/1} } @ARTICLE{nazikian_itb_measurement_2005, author = {R. Nazikian and K. Shinohara and G. J. Kramer and E. Valeo and K. Hill and T. S. Hahm and G. Rewoldt and S. Ide and Y. Koide and Y. Oyama and H. Shirai and W. Tang}, title = {Measurement of Turbulence Decorrelation during Transport Barrier Evolution in a High-Temperature Fusion Plasma}, journal = {Physical Review Letters}, year = {2005}, volume = {94}, pages = {135002-4}, month = apr, url = {http://link.aps.org/abstract/PRL/v94/e135002} } @ARTICLE{neudatchin_analysis_2001, author = {S. V. Neudatchin and T. Takizuka and H. Shirai and T. Fujita and A. Isayama and Y. Koide and Y. Kamada}, title = {Analysis of internal transport barrier heat diffusivity from heat pulse propagation induced by an {ITB} event in {JT-60U} reverse shear plasmas}, journal = {Plasma Physics and Controlled Fusion}, year = {2001}, volume = {43}, pages = {661--675}, number = {5}, abstract = {Internal transport barrier {(ITB)} formation in the positive shear zone of reverse shear {(RS)} plasmas in the {JT-60U} tokamak is described as a series of {ITB} events, which are abrupt in time and wide in space variations of heat diffusivity, observed as the simultaneous rise and decay of the electron temperature Te in two zones. A new source of heat pulse propagation {(HPP)} is found in {RS} plasmas. {HPP} is created by an {ITB} event. For the last {ITB} event described in the present paper, the region of strong ({\textasciitilde}20 {keV} s-1) Te rise is initially well localized ({\textasciitilde}4 cm) in space. Later, a slow diffusive broadening of the rising Te perturbation is seen. Outward {HPP} is analysed in the region with {\textasciitilde}8 cm width fully located in the positive shear space zone. Values of the electron dynamic heat diffusivity as low as {\textasciitilde}0.1 m2 s-1 are found. A similar low value of the ion dynamic heat diffusivity (close to the neoclassical value) is obtained for ion {HPP.} An important consequence of {HPP} analysis is the absence of electron and ion `heat pinch' in the {ITB} region.}, issn = {0741-3335}, url = {http://www.iop.org/EJ/abstract/0741-3335/43/5/303} } @ARTICLE{nevins_review_1998, author = {W. M. Nevins}, title = {A Review of Confinement Requirements for Advanced Fuels}, journal = {Journal of Fusion Energy}, year = {1998}, volume = {17}, pages = {25--32}, number = {1}, month = mar, note = {Nevins argues that without recovery of Bremstrallung losses from {p-B11} fusion, the maximum Q {\textless} 3. He shows that {D-3He} and catalyzed {D-D} are unattractive because a small impurity content dramatically increases their relative radiative losses, and alpha particle ash poses a more severe problem.}, abstract = {The energy confinement requirements for burning {D-3He,} {D-D,} or {P-11B} are reviewed, with particular attention to the effects of helium ash accumulation. It is concluded that the {DT} cycle will lead to the more compact and economic fusion power reactor. The substantially less demanding requirements for ignition in {DT} (the ne {tE} T required for ignition in {DT} is smaller than that of the nearest advanced fuel, {D-3He,} by a factor of 50) will allow ignition, or significant fusion gain, in a smaller device; while the higher fusion power density (the fusion power density in {DT} is higher than that of {D-3He} by a factor of 100 at the same plasma pressure) allows for a more compact and economic device at fixed fusion power.}, doi = {10.1023/A:1022513215080}, url = {http://dx.doi.org/10.1023/A:1022513215080} } @ARTICLE{nevins_can_1995, author = {W. M. Nevins}, title = {Can inertial electrostatic confinement work beyond the ion--ion collisional time scale?}, journal = {Physics of Plasmas}, year = {1995}, volume = {2}, pages = {3804-3819}, month = oct, doi = {10.1063/1.871080}, keywords = {COLLISIONAL PLASMA,COULOMB SCATTERING,ELECTROSTATIC CONFINEMENT,IONION COLLISIONS,NONEQUILIBRIUM PLASMA,RELAXATION TIME,THERMONUCLEAR DEVICES}, url = {http://link.aip.org/link/?PHP/2/3804/1} } @ARTICLE{nevins_discrete_2005, author = {W. M. Nevins and G. W. Hammett and A. M. Dimits and W. Dorland and D. E. Shumaker}, title = {Discrete particle noise in particle-in-cell simulations of plasma microturbulence}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {122305-16}, month = dec, keywords = {noise,plasma instability,plasma simulation,plasma temperature,plasma transport processes,plasma turbulence}, url = {http://link.aip.org/link/?PHP/12/122305/1} } @ARTICLE{noll_computer_1986, author = {Reinhard Noll and Claus R. Haas and Bruno Weikl and Gerd Herziger}, title = {Computer simulation of schlieren images of rotationally symmetric plasma systems: a simple method}, journal = {Applied Optics}, year = {1986}, volume = {25}, pages = {769--774}, number = {5}, month = mar, abstract = {Schlieren techniques are commonly used methods for quantitative analysis of cylindrical or spherical index of refraction profiles. Many schlieren objects, however, are characterized by more complex geometries, so we have investigated the more general case of noncylindrical, rotationally symmetric distributions of index of refraction n(r,z). Assuming straight ray paths in the schlieren object we have calculated {2-D} beam deviation profiles. It is shown that experimental schlieren images of the noncylindrical plasma generated by a plasma focus device can be simulated with these deviation profiles. The computer simulation allows a quantitative analysis of these schlieren images, which yields, for example, the plasma parameters, electron density, and electron density gradients.}, doi = {{10.1364/AO.25.000769}}, shorttitle = {Computer simulation of schlieren images of rotationally symmetric plasma systems}, url = {http://ao.osa.org/abstract.cfm?URI=ao-25-5-769} } @ARTICLE{nygren_fusion_2004, author = {{R.E.} Nygren and {T.D.} Rognlien and {M.E.} Rensink and {S.S.} Smolentsev and {M.Z.} Youssef and {M.E.} Sawan and {B.J.} Merrill and C. Eberle and {P.J.} Fogarty and {B.E.} Nelson and {D.K.} Sze and R. Majeski}, title = {A fusion reactor design with a liquid first wall and divertor}, journal = {Fusion Engineering and Design}, year = {2004}, volume = {72}, pages = {181--221}, number = {1-3}, month = nov, abstract = {Within the magnetic fusion energy program in the {US,} a program called {APEX} is investigating the use of free flowing liquid surfaces to form the inner surface of the chamber around the plasma. As part of this work, the {APEX} Team has investigated several possible design implementations and developed a specific engineering concept for a fusion reactor with liquid walls. Our approach has been to utilize an already established design for a future fusion reactor, the {ARIES-RS,} for the basic chamber geometry and magnetic configuration, and to replace the chamber technology in this design with liquid wall technology for a first wall and divertor and a blanket with adequate tritium breeding. This paper gives an overview of one design with a molten salt (a mixture of lithium, beryllium and sodium fluorides) forming the liquid surfaces and a ferritic steel for the structural material of the blanket. The design point is a reactor with 3840 {MW} of fusion power of which 767 {MW} is in the form of energetic particles (alpha power) and 3073 {MW} is in the form of neutrons. The alpha plus auxiliary power total 909 {MW} of which 430 {MW} is radiated from the core mostly onto the first wall and the balance flows into the edge plasma and is distributed between the first wall and the divertor. In pursuing the application of liquid surfaces in {APEX,} the team has developed analytical tools that are significant achievements themselves and also pursued experiments on flowing liquids. This work is covered elsewhere, but the paper will also note several such areas to indicate the supporting science behind the design presented. Significant new work in modeling the plasma edge to understand the interaction of the plasma with the liquid walls is one example. Another is the incorporation of magneto-hydrodynamic {(MHD)} effects in fluid modeling and heat transfer.}, doi = {10.1016/j.fusengdes.2004.07.007}, issn = {0920-3796}, keywords = {Alpha {power,APEX,Magneto-hydrodynamic} effects}, url = {http://www.sciencedirect.com/science/article/B6V3C-4DD8KYN-1/2/9eae60fc0aa90d7b967099469f4c309a} } @ARTICLE{PhysRevB.17.1052, author = {Oechsner, H.}, title = {Electron yields from clean polycrystalline metal surfaces by noble-gas-ion bombardment at energies around 1 keV}, journal = {Phys. Rev. B}, year = {1978}, volume = {17}, pages = {1052--1056}, number = {3}, month = {Feb}, doi = {10.1103/PhysRevB.17.1052}, keywords = {secondary electron emission, 1yr_project}, numpages = {4}, publisher = {American Physical Society} } @ARTICLE{oksuz_understanding_2004, author = {L. Oksuz and N. Hershkowitz}, title = {Understanding Mach probes and Langmuir probes in a drifting, unmagnetized, non-uniform plasma}, journal = {Plasma Sources Science and Technology}, year = {2004}, volume = {13}, pages = {263-271}, abstract = {The effects of non-uniform drifting plasmas (in presheaths) on planar Langmuir probes and Mach probes are investigated in an unmagnetized argon plasma. Mach probe data are compared with double-sided Langmuir probe data. The calculated plasma potential from the Langmuir probe is found to be approximately equal to the average of the plasma potentials calculated from data on each side of the Mach probe. A new method is presented to determine the ion drift velocity using the electron saturation currents for um < 1 where um is the Mach number. This approach has the advantage that it uses much higher currents. It is shown that a single-sided planar probe gives information about the plasma almost an ion-neutral collision length away from the probe and should not be used in drifting plasma. The one-sided Langmuir probe on the downstream side of the Mach probe indicates the plasma potential where the ion drift velocity is zero and a one-sided Langmuir probe on the upstream side of the Mach probe also indicates the plasma potential where the ion drift velocity is zero.}, doi = {10.1088/0963-0252/13/2/010}, issn = {0963-0252} } @INPROCEEDINGS{okubo_characteristics_1999, author = {M. Okubo and N. Mizuguchi and S. Okada and S. Goto}, title = {Characteristics of a novel ion energy spectrum f(E[sub ||],E[sub [perpendicular]]) analyzer in measurements of plasma flow in a magnetic mirror throat}, booktitle = {Proceedings of the 12th topical conference on high temperature plasma diagnostics}, year = {1999}, volume = {70}, pages = {853-856}, address = {Princeton, New Jersey (USA)}, publisher = {AIP}, doi = {10.1063/1.1149446}, journal = {Proceedings of the 12th topical conference on high temperature plasma diagnostics}, keywords = {magnetic mirrors,plasma diagnostics,plasma flow}, url = {http://link.aip.org/link/?RSI/70/853/1} } @ARTICLE{ono_exploration_2000, author = {M. Ono and {S.M.} Kaye and {Y.-K.M.} Peng and G. Barnes and W. Blanchard and {M.D.} Carter and J. Chrzanowski and L. Dudek and R. Ewig and D. Gates and {R.E.} Hatcher and T. Jarboe and {S.C.} Jardin and D. Johnson and R. Kaita and M. Kalish and {C.E.} Kessel and {H.W.} Kugel and R. Maingi and R. Majeski and J. Manickam and B. {McCormack} and J. Menard and D. Mueller and {B.A.} Nelson and {B.E.} Nelson and C. Neumeyer and G. Oliaro and F. Paoletti and R. Parsells and E. Perry and N. Pomphrey and S. Ramakrishnan and R. Raman and G. Rewoldt and J. Robinson and {A.L.} Roquemore and P. Ryan and S. Sabbagh and D. Swain and {E.J.} Synakowski and M. Viola and M. Williams and {J.R.} Wilson and {NSTX} Team}, title = {Exploration of spherical torus physics in the {NSTX} device}, journal = {Nuclear Fusion}, year = {2000}, volume = {40}, pages = {557--561}, number = {{3Y}}, abstract = {The National Spherical Torus Experiment {(NSTX)} is being built at Princeton Plasma Physics Laboratory to test the fusion physics principles for the spherical torus concept at the {MA} level. The {NSTX} nominal plasma parameters are R0 = 85 cm, a = 67 cm, R/a [?] 1.26, Bt = 3 {kG,} Ip = 1 {MA,} q95 = 14, elongation k [?] 2.2, triangularity d [?] 0.5 and a plasma pulse length of up to 5 s. The plasma heating/current drive tools are high harmonic fast wave (6 {MW,} 5 s), neutral beam injection (5 {MW,} 80 {keV,} 5 s) and coaxial helicity injection. Theoretical calculations predict that {NSTX} should provide exciting possibilities for exploring a number of important new physics regimes, including very high plasma b, naturally high plasma elongation, high bootstrap current fraction, absolute magnetic well and high pressure driven sheared flow. In addition, the {NSTX} programme plans to explore fully non-inductive plasma startup as well as a dispersive scrape-off layer for heat and particle flux handling.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/-link=8949239/0029-5515/40/3Y/316} } @ARTICLE{diamondreview2005, author = {P H Diamond, S-I Itoh, K Itoh and T S Hahm}, title = {Zonal flows in plasma\—a review}, journal = {Plasma Physics and Controlled Fusion}, year = {2005}, volume = {47}, pages = {R35-R161}, number = {5}, abstract = {A comprehensive review of zonal flow phenomena in plasmas is presented. While the emphasis is on zonal flows in laboratory plasmas, planetary zonal flows are discussed as well. The review presents the status of theory, numerical simulation and experiments relevant to zonal flows. The emphasis is on developing an integrated understanding of the dynamics of drift wave-zonal flow turbulence by combining detailed studies of the generation of zonal flows by drift waves, the back-interaction of zonal flows on the drift waves, and the various feedback loops by which the system regulates and organizes itself. The implications of zonal flow phenomena for confinement in, and the phenomena of fusion devices are discussed. Special attention is given to the comparison of experiment with theory and to identifying directions for progress in future research.}, url = {http://stacks.iop.org/0741-3335/47/R35} } @ARTICLE{palluel_experimental-study_1980, author = {P. PALLUEL and AM SHROFF}, title = {EXPERIMENTAL-STUDY OF IMPREGNATED-CATHODE BEHAVIOR, EMISSION, AND LIFE}, journal = {Journal of Applied Physics}, year = {1980}, volume = {51}, pages = {2894-2902}, note = {The evolution of the electron emission of impregnated cathodes has been measured over many thousands of hours of operation at various temperatures in diodes and traveling-wave tubes. Certain physical methods were used to investigate the correlation between these results and the mechanisms of cathode operation: X-ray fluorescence electron microprobe analysis has given a new access to the study of the consumption of the active materials (barium and calcium) at various stages of cathode life. While barium depletes according to the t1/2 law, an approximate t1/3 law found for calcium could result from a two-step process in the barium and calcium chemistry. The formation and desorption of synthetized emissive layers on a nonimpregnated porous tungsten plug in a Becker-type test diode is one way to investigate the properties of emissive surfaces. The behavior of layers synthetized at low temperatures onto active impregnated cathodes suggests a surface equilibrium depending on the chemical nature of the substrate. Emission charts are proposed to compare, over a large range of temperatures, the different types of cathodes, in particular, the characteristics of uncoated and coated ones. Journal of Applied Physics is copyrighted by The American Institute of Physics.}, issn = {0021-8979}, keywords = {Physics, Applied} } @ARTICLE{pareschi_fast_2000, author = {L. Pareschi and G. Russo and G. Toscani}, title = {Fast Spectral Methods for the Fokker-Planck-Landau Collision Operator}, journal = {Journal of Computational Physics}, year = {2000}, volume = {165}, pages = {216-236}, month = nov, abstract = {In this paper we present a new spectral method for the fast evaluation of the Fokker-Planck-Landau (FPL) collision operator. The method allows us to obtain spectrally accurate numerical solutions with simply O(n log2n) operations in contrast with the usual O(n2) cost of a deterministic scheme. We show that the method preserves the total mass whereas momentum and energy are approximated with spectral accuracy. Numerical results for the FPL equation for Maxwell molecules and for Coulomb interactions in two and three dimensions in velocity space are also given.}, doi = {10.1006/jcph.2000.6612}, url = {http://www.sciencedirect.com/science/article/B6WHY-45FC8B5-13/2/f5494a42163d57e940f0abbae289d16f} } @ARTICLE{park_plasma_1999, author = {W. Park and E. V. Belova and G. Y. Fu and X. Z. Tang and H. R. Strauss and L. E. Sugiyama}, title = {Plasma simulation studies using multilevel physics models}, journal = {The 40th annual meeting of the division of plasma physics of the american physical society}, year = {1999}, volume = {6}, pages = {1796--1803}, month = may, doi = {10.1063/1.873437}, keywords = {{COMPUTER} {CODES,COMPUTERIZED} {SIMULATION,PLASMA} {SIMULATION,THREE-DIMENSIONAL} {CALCULATIONS}}, url = {http://link.aip.org/link/?PHP/6/1796/1} } @INCOLLECTION{pastukhov_classical_1984, author = {Pastukhov, V.~P.}, title = {Classical Longitudinal Plasma Losses from Open Adiabatic Traps}, booktitle = {Reviews of Plasma Physics}, publisher = {Consultants Bureau}, year = {1984}, editor = {Kadomtsev, B. B}, volume = {13}, pages = {203--259}, address = {New York}, keywords = {mirrors, open systems, 2yr_project}, owner = {erikg}, timestamp = {2007.12.06} } @ARTICLE{paul_novel_2007, author = {R. K. Paul}, title = {Novel approach to Abel inversion}, journal = {Review of Scientific Instruments}, year = {2007}, volume = {78}, pages = {093701--5}, number = {9}, doi = {10.1063/1.2777159}, keywords = {emissivity, integral equations, inverse problems, plasma diagnostics, spectroscopy, Tokamak devices}, url = {http://link.aip.org/link/?RSI/78/093701/1} } @ARTICLE{pearlstein69, author = {Pearlstein and Berk}, journal = {Physics Review Letters}, year = {1969}, volume = {23}, pages = {220}, keywords = {GPP2, sheared slab analysis, drift waves, univseral drift instability, collisionless electron drift wave}, owner = {erikg}, timestamp = {2007.05.09} } @TECHREPORT{astra_report_2002, author = {G.V.~Pereverzev and P.N.~Yushmanov}, title = {ASTRA---Automated System for Transport Analysis in a Tokamak}, institution = {IPP Garching}, year = {2002}, type = {Report}, month = {FEB}, owner = {erikg}, timestamp = {2009.07.17}, url = {http://edoc.mpg.de/282186}, volume = {IPP5/98} } @ARTICLE{petry_secondary_1926, author = {Robert L. Petry}, title = {Secondary Electron Emission from Tungsten, Copper and Gold}, journal = {Physical Review}, year = {1926}, volume = {28}, pages = {362}, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, url = {http://link.aps.org/abstract/PR/v28/p362} } @UNPUBLISHED{phelps_collision_data, author = {Phelps, A. V.}, title = {ftp://jila.colorado.edu/collision_data/}, note = {unpublished}, owner = {erikg}, timestamp = {2008.05.22}, url = {ftp://jila.colorado.edu/collision_data/} } @ARTICLE{phelps_application_1994, author = {A. V. Phelps}, title = {The application of scattering cross sections to ion flux models in discharge sheaths}, journal = {Journal of Applied Physics}, year = {1994}, volume = {76}, pages = {747-753}, month = jul, doi = {10.1063/1.357820}, keywords = {ANGULAR DISTRIBUTION,ARGON IONS,CROSS SECTIONS,ELECTRIC DISCHARGES,ION COLLISIONS,ION FLUX,MONTE CARLO METHOD,PLASMA SHEATH,SCATTERING}, url = {http://link.aip.org/link/?JAP/76/747/1} } @ARTICLE{pigarov_simulation_2007, author = {{A.Yu.} Pigarov and {S.I.} Krasheninnikov and B. {LaBombard} and {T.D.} Rognlien}, title = {Simulation of large parallel plasma flows in the tokamak {SOL} driven by cross-field transport asymmetries}, journal = {Journal of Nuclear Materials}, year = {2007}, volume = {363-365}, pages = {643--648}, month = jun, abstract = {{Large-Mach-number} parallel plasma flows in the single-null {SOL} of different tokamaks are simulated with multifluid transport code {UEDGE.} The key role of poloidal asymmetry of cross-field plasma transport as the driving mechanism for such flows is discussed. The impact of ballooning-like diffusive and convective transport and plasma flows on divertor detachment, material migration, impurity flows, and erosion/deposition profiles is studied. The results on well-balanced double null plasma modeling that are indicative of strong asymmetry of cross-field transport are presented.}, doi = {10.1016/j.jnucmat.2007.01.268}, issn = {0022-3115}, keywords = {Cross-field {transport,Edge} {plasma,Impurity} {transport,Plasma} {flow,UEDGE}}, url = {http://www.sciencedirect.com/science/article/B6TXN-4N3GHR0-1/2/56b8f440a121ff3a2deb76574b6116a2} } @ARTICLE{plihon_experimental_2007, author = {N. Plihon and P. Chabert and {C.S.} Corr}, title = {Experimental investigation of double layers in expanding plasmas}, journal = POP, year = {2007}, volume = {14}, pages = {013506}, note = {DL can be thought of as a sheath separating plasmas of different potentials. Static, current-free DLs in low-pressure expanding plasmas are of special interest because they might be used in space propulsion. This study examined an RF driven electropositive plasma. Diagnostics: Langmuir probe: used second derivative technique to find the electron energy probability function (eepf), $V_p$, and $n_e$ was determined by the current at $V_p$. RFEA: downstream of the DL, a two-peaked IEDF is expected: ions centered at $V_p$ generated in the downstream flow and beam ions created upstream and accelerated through the DL. Ions in the first peak are accelerated at $v_{Bohm}$ when entering the sheath in front of the RFEA, and the local plasma density can be computed by $n_p = \frac{\Gamma_p}{eG^4v_{Bohm}}$ DL measurements: The potential drop across the DL can be measured: $\Phi_{DL}=V_b-V_p$. They were unable to measure $V_p$ across the DL directly using a Langmuir probe; it disturbed the plasma too much. The derivative of plux was calculated assuming both flat DL profile (poor fit) and hemispherical DL. DL formation was strongly dependent on B field magnitude and operating pressure. A minimum critical (divergent) B field is necessary for DL formation, but increasing B field strength did not substantially increase $\Phi_{DL}$; however B field topology and system geometry may play important roles. The position of the DL is near the position of the maximum in the B field gradient. $\Phi_{DL}$ is sensitive to pressure, decreasing as pressure increases from 0.1 mTorr to 1 mTorr. The beam flux also decreases due to increased collisionality and decreased acceleration. The Chen model (ref 21) assumes the plasma is frozen to B field lines ($\omega_{ce}/\nu_{e,coll}>>1$, and $\Phi_{DL}$ is dependent on $T_e$ and the plasma column must expand radially for DL formation. the Lieberman model (ref 20) explicitly accounts for the pressure dependence of the DL and catches all of the pressure features, but does not account for a B field. Time-resolved DL formation: The DL forms less than 30 $\mu$s after breakdown, with the beam potential reaching its steady-state value, then $V_p$, and finally much later steady-state density is reached. Boundary conditions appear to only weakly affect the DL characteristics, and DLs were formed in a partially grounded (DL could be current-carrying) or entirely insulating or floating (DL must be current-free) cases.}, file = {\\Docs\\Double Layers\\plihon07.pdf:\\Docs\\Double Layers\\plihon07.pdf:PDF}, keywords = {double layers, plasma expansion, 1yr_project} } @ARTICLE{porkolab_phase_2006, author = {M. Porkolab and {J.C.} Rost and N. Basse and J. Dorris and E. Edlund and Liang Lin and Y. Lin and S. Wukitch}, title = {Phase contrast imaging of waves and instabilities in high temperature magnetized fusion plasmas}, journal = {Plasma Science, {IEEE} Transactions on}, year = {2006}, volume = {34}, pages = {229--234}, number = {2}, abstract = {Phase contrast imaging {(PCI)} is an internal reference beam interferometry technique which provides a direct image of line integrated plasma density fluctuations. The method has been used with great success to measure waves and turbulence in magnetically confined high temperature plasmas. The principle of {PCI} was developed in optics in the 1930s by the Dutch physicist Zernike, leading to the development of phase-contrast microscopy. The technique allows one to detect the variation of the index of refraction of a dielectric medium (such as a plasma) due to the presence of waves or turbulent fluctuations. The image produced by the introduction of a phase plate in the beam path, and subsequently imaging the expanded laser beam onto a detector array can be used to calculate wavelengths and correlation lengths of fluctuations in high temperature plasmas. In this paper, the principle of {PCI} is summarized and examples of measurements from the {DIII-D} and Alcator {C-Mod} tokamak plasmas are given.}, doi = {{10.1109/TPS.2006.872181}}, issn = {0093-3813}, keywords = {Alcator C-Mod tokamak,correlation lengths,DIII-D tokamak,high temperature magnetized fusion plasmas,internal reference beam interferometry,laser beam,line integrated plasma density fluctuations,magnetically confined high temperature plasmas,phase contrast imaging,phase contrast imaging,phase-contrast microscopy,plasma density,plasma diagnostics,plasma dielectric properties,plasma fluctuations,plasma instabilities,plasma instability,plasma light propagation,plasmas,plasma temperature,plasma turbulence,plasma waves,refractive index,Tokamak devices,tokamak plasmas,turbulence,waves,pci} } @INPROCEEDINGS{porte_design_1999, author = {L. Porte and C. L. Rettig and W. A. Peebles and X. Ngyuen}, title = {Design and operation of a low cost, reliable millimeter-wave interferometer}, booktitle = {Proceedings of the 12th topical conference on high temperature plasma diagnostics}, year = {1999}, volume = {70}, pages = {1082-1084}, address = {Princeton, New Jersey (USA)}, publisher = {AIP}, doi = {10.1063/1.1149372}, journal = {Proceedings of the 12th topical conference on high temperature plasma diagnostics}, keywords = {COST,DESIGN,INTERFEROMETERS,millimetre wave measurement,millimetre wave propagation,OPERATION,PLASMA DENSITY,plasma turbulence,TOKAMAK DEVICES,TURBULENCE}, url = {http://link.aip.org/link/?RSI/70/1082/1} } @ARTICLE{porter_particle_2001, author = {{G.D.} Porter and {T.D.} Rognlien and {M.E.} Rensink and {N.S.} Wolf and {W.P.} West}, title = {Particle flows in pumped {DIII-D} discharges}, journal = {Journal of Nuclear Materials}, year = {2001}, volume = {290-293}, pages = {692--695}, month = mar, abstract = {The dynamics of particle flows in the {DIII-D} tokamak for two divertor configurations is considered. Fuel and intrinsic carbon impurity flows are analyzed using experimental data and {2D} fluid plasma simulations. The flows in puff and pump experiments done in open and closed divertor geometries are described. It is shown that the flow of fuel particles is sensitive to divertor geometry. The pumping efficiency of the {DIII-D} cryopumps is a factor of 2 higher in a closed geometry than an open. The core refueling rate of an open divertor is a factor of 2 higher than that of a closed divertor. In contrast, the flow of impurity carbon particles is insensitive to divertor geometry. Both the core carbon content and the fraction of the carbon source which penetrates to the core are unchanged between open and closed divertors. In addition, the core impurity content is found to be insensitive to the amplitude of gas puffing in the simulations.}, doi = {{10.1016/S0022-3115(00)00448-7}}, issn = {0022-3115}, keywords = {Impurity, Modelling, {UEDGE}}, url = {http://www.sciencedirect.com/science/article/B6TXN-42K5JDD-5P/2/62e58abfbcc31f5c75ded2d6d409b3d4} } @ARTICLE{presby_plasma_1967, author = {Herman M. Presby and David Finkelstein}, title = {Plasma Phasography}, journal = {Review of Scientific Instruments}, year = {1967}, volume = {38}, pages = {1563-1572}, month = nov, doi = {10.1063/1.1720602}, keywords = {phase contrast}, url = {http://link.aip.org/link/?RSI/38/1563/1} } @INCOLLECTION{prothero_local-error_1969, author = {A. Prothero}, title = {Local-error estimates for variable-step {Runge-Kutta} methods}, booktitle = {Conference on the Numerical Solution of Differential Equations}, year = {1969}, pages = {228--233}, abstract = {Estimates of the local errors arising in the solution of initial-value problems by {Runge-Kutta} methods may be obtained without additional computation by considering two or more integration steps together. For a given {Runge-Kutta} method, the parameters occurring in the local-error formula must satisfy a given set of linear equations. General solutions for second-, third- and fourth-order {Runge-Kutta} methods are given. Typical integration times for a variable-step fourth-order {Runge-Kutta} method incorporating such an error estimate are 30\% shorter than those for the same method using the well-known step-halving estimates.}, url = {http://dx.doi.org/10.1007/BFb0060033} } @ARTICLE{qin_geometric_2007, author = { H Qin and {RH} Cohen and {WM} Nevins and {XQ} Xu}, title = {Geometric gyrokinetic theory for edge plasmas}, journal = {{PHYSICS} {OF} {PLASMAS}}, year = {2007}, volume = {14}, number = {5}, month = may, abstract = {It turns out that gyrokinetic theory can be geometrically formulated as a special case of a geometrically generalized {Vlasov-Maxwell} system. It is proposed that the phase space of the space-time is a seven-dimensional fiber bundle P over the four-dimensional space-time M, and that a {Poincare-Cartan-Einstein} 1-form gamma on the seven-dimensional phase space determines a particle's worldline in the phase space. Through Liouville 6-form Omega and fiber integral, the 1-form gamma also uniquely defines a geometrically generalized {Vlasov-Maxwell} system as a field theory for the collective electromagnetic field. The geometric gyrokinetic theory is then developed as a special case of the geometrically generalized {Vlasov-Maxwell} system. In its most general form, gyrokinetic theory is about a symmetry, called gyrosymmetry, for magnetized plasmas, and the 1-form gamma again uniquely defines the gyrosymmetry. The objective is to decouple the gyrophase dynamics from the rest of the particle dynamics by finding the gyrosymmetry in gamma. Compared to other methods of deriving the gyrokinetic equations, the advantage of the geometric approach is that it allows any approximation based on mathematical simplification or physical intuition to be made at the 1-form level, and yet the field theories still have the desirable exact conservation properties, such as phase space volume conservation and energy-momentum conservation if the 1-form does not depend on the space-time coordinate explicitly. A set of generalized gyrokinetic equations valid for the edge plasmas is then derived using this geometric method. This formalism allows large-amplitude, time-dependent background electromagnetic fields to be developed fully nonlinearly in addition to small-amplitude, short-wavelength electromagnetic perturbations. The fact that we adopted the geometric method in the present study does not necessarily imply that the major results reported here cannot be achieved using classical methods. What the geometric method offers is a systematic treatment and simplified calculations. {(C)} 2007 American Institute of Physics.}, doi = {10.1063/1.2472596}, issn = {{1070-664X}}, url = {http://apps.isiknowledge.com/full_record.do?product=WOS&search_mode=AuthorFinder&qid=2&SID=1Dl9P6J367@AakpdBLC&page=2&doc=15&cacheurlFromRightClick=no} } @ARTICLE{qin_general_2006, author = { H Qin and {RH} Cohen and {WM} Nevins and {XQ} Xu}, title = {General gyrokinetic equations for edge plasmas}, journal = {{CONTRIBUTIONS} {TO} {PLASMA} {PHYSICS}}, year = {2006}, volume = {46}, pages = {477--489}, number = {7-9}, abstract = {During the pedestal cycle of H-mode edge plasmas in tokamak experiments, large-amplitude pedestal build-up and destruction coexist with small-amplitude drift wave turbulence. The pedestal dynamics simultaneously includes fast time-scale electromagnetic instabilities, long time-scale turbulence-induced transport processes, and more interestingly the interaction between them. To numerically simulate the pedestal dynamics from first principles, it is desirable to develop an effective algorithm based on the gyrokinetic theory. However, existing gyrokinetic theories cannot treat fully nonlinear electromagnetic perturbations with multi-scale-length structures in spacetime, and therefore do not apply to edge plasmas. A set of generalized gyrokinetic equations valid for the edge plasmas has been derived. This formalism allows large-amplitude, time-dependent background electromagnetic fields to be developed fully nonlinearly in addition to small-amplitude, short-wavelength electromagnetic perturbations. It turns out that the most general gyrokinetic theory can be geometrically formulated. The {Poincare-Cartan-Einstein} 1-form on the {7D} phase space determines particles' worldlines in the phase space, and realizes the momentum integrals in kinetic theory as fiber integrals. The infinitesimal generator of the gyro-symmetry is then asymptotically constructed as the base for the gyrophase coordinate of the gyrocenter coordinate system. This is accomplished by applying the Lie coordinate perturbation method to the {Poincare-Cartan-Einstein} 1-form. General gyrokinetic {Vlasov-Maxwell} equations are then developed as the {Vlasov-Maxwell} equations in the gyrocenter coordinate system, rather than a set of new equations. Because the general gyrokinetic system developed is geometrically the same as the {Vlasov-Maxwell} equations, all the coordinate-independent properties of the {Vlasov-Maxwell} equations, such as energy conservation, momentum conservation, and phase space volume conservation, are automatically carried over to the general gyrokinetic system. The pullback transformation associated with the coordinate transformation is shown to be an indispensable part of the general gyrokinetic {Vlasov-Maxwell} equations. As an example, the pullback transformation in the gyrokinetic Poisson equation is explicitly expressed in terms of moments of the gyrocenter distribution function, with the important gyro-orbit squeezing effect due to the large electric field shearing in the edge and the full finite Larmour radius effect for short wavelength fluctuations. The familiar "polarization drift density" in the gyrocenter Poisson equation is replaced by a more general expression. (c) 2006 {WILEY-VCH} Verlag {GmbH} \& Co. {KGaA,} Weinheim.}, doi = {10.1002/ctpp.200610034}, issn = {0863-1042}, url = {http://apps.isiknowledge.com/full_record.do?product=WOS&search_mode=AuthorFinder&qid=2&SID=1Dl9P6J367@AakpdBLC&page=2&doc=17&cacheurlFromRightClick=no} } @ARTICLE{qin_exact_magnetic_moment_2006, author = {Hong Qin and Ronald C. Davidson}, title = {An Exact Magnetic-Moment Invariant of Charged-Particle Gyromotion}, journal = {Physical Review Letters}, year = {2006}, volume = {96}, pages = {085003-4}, month = mar, keywords = {magnetic moments,plasma theory}, url = {http://link.aps.org/abstract/PRL/v96/e085003} } @ARTICLE{qin_symmetries-invariants_oscillator-envelope_2006, author = {Qin, Hong and Davidson, Ronald C.}, title = {Symmetries and invariants of the oscillator and envelope equations with time-dependent frequency}, journal = {Phys. Rev. ST Accel. Beams}, year = {2006}, volume = {9}, pages = {054001}, number = {5}, month = {May}, doi = {10.1103/PhysRevSTAB.9.054001}, numpages = {5}, publisher = {American Physical Society} } @ARTICLE{bickerton72, author = {R.Bickerton, et.al}, journal = {Nuclear Fusion}, year = {1972}, volume = {12}, pages = {609}, keywords = {GPP2, bootstrap current}, owner = {Administrator}, timestamp = {2007.04.07} } @TECHREPORT{ltx2007proposal, author = {{R.~Majeski} and {R.~Kaita} and {L.~Zakharov}}, title = {The lithium tokamak experiment (LTX)}, institution = {PPPL DoE proposal}, year = {2007}, note = {Goal is to develop/demonstrate LiWall confinement regime controlled by neoclassical diffusion and not sensitive to anomalous electron energy losses in both ohmic and NBI plasmas. Characteristics are high edge pedestal temp., stable ELM-free, and confinement time close to neoclassical value. This will test existing transport theory and study particle transport with no uncontrolled edge source. Also, plasma stabilization by a conducting wall at a high-temp boundary can be tested. Li walls can enable small devices to test new confinement concepts, because they won't be wall-dominated. Questions: How do you get NBI through Li?}, keywords = {lithium, plasma facing components, recycling}, owner = {erikg}, timestamp = {2007.08.20} } @ARTICLE{raitses_parametric_2001, author = {Y. Raitses and N. J. Fisch}, title = {Parametric investigations of a nonconventional Hall thruster}, journal = {Physics of Plasmas}, year = {2001}, volume = {8}, pages = {2579-2586}, doi = {10.1063/1.1355318}, keywords = {plasma devices; thrusters; 1yr_project}, location = {Quebec City, Quebec (Canada)}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/8/2579/1} } @ARTICLE{raitses_enhanced_2007, author = {Y. Raitses and A. Smirnov and N. J. Fisch}, title = {Enhanced performance of cylindrical Hall thrusters}, journal = {Applied Physics Letters}, year = {2007}, volume = {90}, pages = {221502}, number = {22}, eid = {221502}, note = {includes thrust measurements at MAE in 2006 and IEDF RPA measurements from early 2007 claims: 30--40\% anode efficiency at 100-200W discharge power: $P_d = V_d I_d$. Also mentions that ion energy is shifted to about 30 eV higher energy in the current overrun regime, which he claims is partially explained by a reduced cathode voltage drop required to sustain the thruster discharge, quoting ref. 16. I thought we showed that the increased ion energy is not due to a cathode voltage change. Quotes specifically using 2.6 cm thruster, $V_d = 250$V, flow: 4 sccm, plume angle reduced from $74^\circ $ to about $55^\circ $ when $I_d$ increased from 0.57 A to 0.66 A, and current utilization changes only insignificantly: from 73\% to 71\%. Also quotes for the 3 cm thruster under same conditions the plume ancle changed from $62^\circ $ to $50^\circ $ and the current utilization changed from 71\% to 66\%. Also said that the 3 cm thruster already produces a narrower plume, and that any further reduction is hard to realize.}, doi = {10.1063/1.2741413}, keywords = {plasma accelerators; plasma magnetohydrodynamics; ionization; plasma transport processes, Hall thrusters, 1yr_project}, publisher = {AIP}, url = {http://link.aip.org/link/?APL/90/221502/1} } @ARTICLE{raitses_operation_2006, author = {Y. Raitses and D. Staack and A. Dunaevsky and N. J. Fisch}, title = {Operation of a segmented Hall thruster with low-sputtering carbon-velvet electrodes}, journal = {Journal of Applied Physics}, year = {2006}, volume = {99}, pages = {036103-3}, month = feb, doi = {DOI:10.1063/1.2168023}, keywords = {arcs (electric),carbon fibres,electrodes,plasma magnetohydrodynamics,plasma-wall interactions,sputtering}, url = {http://link.aip.org/link/?JAP/99/036103/1} } @ARTICLE{2005PhPl...12e7104R, author = {{Raitses}, Y. and {Staack}, D. and {Keidar}, M. and {Fisch}, N.~J.}, title = {{Electron-wall interaction in Hall thrusters}}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {7104-+}, month = may, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/2005PhPl...12e7104R}, doi = {10.1063/1.1891747}, keywords = {Hall thrusters, 1yr_project} } @ARTICLE{ram_mode_1996, author = {A. K. Ram and A. Bers and S. D. Schultz and V. Fuchs}, title = {Mode conversion of fast Alfv[e-acute]n waves at the ion--ion hybrid resonance}, journal = {Physics of Plasmas}, year = {1996}, volume = {3}, pages = {1976--1982}, number = {5}, month = may, doi = {10.1063/1.871677}, keywords = {alfven waves, Bernstein waves, EBW, electron Bernstein wave, mode conversion, IBW, ion Bernstein wave, radiofrequency heating, rf heating}, url = {http://link.aip.org/link/?PHP/3/1976/1} } @ARTICLE{ram_excitation_2000, author = {A. K. Ram and S. D. Schultz}, title = {Excitation, propagation, and damping of electron Bernstein waves in tokamaks}, journal = {Physics of Plasmas}, year = {2000}, volume = {7}, pages = {4084--4094}, number = {10}, month = oct, doi = {10.1063/1.1289689}, keywords = {alfven waves, Bernstein waves, EBW, electron Bernstein wave, mode conversion, IBW, ion Bernstein wave, wave heating,ray tracing}, url = {http://link.aip.org/link/?PHP/7/4084/1} } @ARTICLE{ram_excitation_2003, author = {{A.K.} Ram and A. Bers}, title = {Excitation and emission of electron cyclotron waves in spherical tori}, journal = {Nuclear Fusion}, year = {2003}, volume = {43}, pages = {1305--1312}, number = {11}, note = {In equation 7, his psi function is the digamma function: digamma(x)=gamma'(x)/gamma(x)}, abstract = {The conventional ordinary and extraordinary modes in the electron cyclotron range of frequencies are not suitable for heating of and/or driving currents in spherical tori {(ST)} plasmas. However, electron Bernstein waves {(EBWs)} offer an attractive possibility for heating and current drive in this range of frequencies. In this paper, we summarize our theoretical and numerical results that describe the excitation of {EBWs} in {ST} plasmas when the extraordinary mode or the ordinary mode are coupled into the plasma from an external source. In our discussion on the conversion of the ordinary mode to {EBWs} (via the slow extraordinary mode) we illustrate very important physics, relevant to this conversion process, that has been ignored in previous studies. This particular physics has to do with the conversion of the slow extraordinary mode to the fast extraordinary mode that can then propagate out of the plasma and thus reduce the mode conversion to {EBWs.} This reduction in the mode conversion can occur even when the wave numbers are such that the ordinary mode cutoff and the slow extraordinary mode cutoff are coincident in space. Furthermore, we also consider the emission of {EBWs} from a thermal plasma. This emission mode converts to extraordinary and ordinary modes in the vicinity of the upper hybrid resonance. We describe the general relationship between the conversion coefficients when exciting {EBWs} using either the extraordinary mode or the ordinary mode, and the emission coefficients when thermally emitted {EBWs} convert to the extraordinary and ordinary modes.}, issn = {0029-5515}, keywords = {EBW, electron bernstein wave}, url = {http://www.iop.org/EJ/abstract/0029-5515/43/11/002} } @ARTICLE{rax_autoresonant_2007, author = {J.-M. Rax and J. Robiche and N. J. Fisch}, title = {Autoresonant ion cyclotron isotope separation}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {043102-8}, month = apr, keywords = {ion beams,isotope separation,plasma-beam interactions,plasma electromagnetic wave propagation,plasma radiofrequency heating}, url = {http://link.aip.org/link/?PHP/14/043102/1} } @INPROCEEDINGS{reis_design_1999, author = {{E.E.} Reis and {C.B.} Baxi and {A.S.} Bozek}, title = {Design and analysis of the cryopump for the {DIII-D} upper divertor }, booktitle = {Fusion Engineering, 1999. 18th Symposium on}, year = {1999}, pages = {519--522}, abstract = {A cryocondensation pump for the upper inboard divertor on {DIII-D} is to be installed in the vacuum vessel in the fall of 1999. The cryopump removes neutral gas particles from the divertor and prevents recycling to the plasma. This pump is designed for a pumping speed of 18,000 l/s at 0.4 {mTorr.} The cryopump is toroidally continuous to minimize inductive voltages and avoid electrical breakdown during disruptions. The cryopump consists of a 25 mm Inconel tube cooled by liquid helium and is surrounded by nitrogen cooled shields. A segmented ambient temperature radiation/particle shield protects the nitrogen shields. The pump is subjected to a steady state heat load of less than 10 W due to conduction and radiation heat transfer}, doi = {{10.1109/FUSION.1999.849892}}, keywords = {0.4 mtorr, 25 mm, cryocondensation pump, cryopump design, cryopumping, {DIII-D} tokamak, {DIII-D} upper divertor, disruptions, fusion reactor, fusion reactor design, fusion reactor divertors, He, inboard divertor, Inconel tube, neutral gas particles, shield, vacuum vessel} } @INPROCEEDINGS{riccio_dynamic_2008, author = {M. Riccio and G. Breglio and A. Irace and P. Spirito}, title = {A dynamic temperature mapping system with a 320x256 pixels frame size and 100kHz sampling rate}, booktitle = {Microelectronics, 2008. MIEL 2008. 26th International Conference on}, year = {2008}, pages = {371-374}, abstract = {A novel temperature mapping system is developed to map ultrafast temperature transients distribution on electronic devices using an infrared thermo-camera . While, in principle, it should be necessary to have a high acquisition rate, our system is based on a standard infrared camera with 50 Hz frame rate together with the widely used equivalent time sampling concept which is adapted to this temperature acquisition system. This is possible because the thermo-camera is equipped with a very fast and sensitive Focal Plane Array of InSb sensors that have a minimum integration time of 10 mus, and a custom digital circuit allows the perfect synchronization between periodical experiment and the acquisition and storage of thermal images. The latter has been realized by the usage of a fully programmable FPGA digital circuit, which generates all the signals needed for the synchronization of the IR camera, the experiment, and data acquisition personal computer. In this paper we describe this system and show, with experiments, how this is capable of detecting temperature transients with an equivalent bandwidth of 100 kHz full frame, far beyond the capabilities of the fastest available IR cameras.}, doi = {10.1109/ICMEL.2008.4559299}, journal = {Microelectronics, 2008. MIEL 2008. 26th International Conference on}, keywords = {data acquisition personal computer,electronic devices,equivalent time sampling,field programmable gate arrays,focal plane array,focal planes,FPGA digital circuit,frequency 100 kHz,image sensors,infrared detectors,InSb,IR camera} } @ARTICLE{riemann_theory_1994, author = {K.-U. Riemann}, title = {Theory of the collisional presheath in an oblique magnetic field}, journal = {Physics of Plasmas}, year = {1994}, volume = {1}, pages = {552-558}, month = mar, doi = {10.1063/1.870800}, keywords = {BOHM CRITERION,BOUNDARY LAYERS,DEBYE LENGTH,HYDRODYNAMIC MODEL,ION COLLISIONS,MAGNETIC FIELDS,PLASMA SHEATH,PLASMAWALL INTERACTIONS,SPACE CHARGE,TRANSPORT THEORY}, url = {http://link.aip.org/link/?PHP/1/552/1} } @ARTICLE{riemann_plasma_1992, author = {K.-U. Riemann}, title = {Plasma - sheath transition and Bohm criterion}, journal = {Contributions to Plasma Physics}, year = {1992}, volume = {32}, pages = {231-236}, abstract = {No Abstract.}, doi = {10.1002/ctpp.2150320309}, url = {http://dx.doi.org/10.1002/ctpp.2150320309} } @ARTICLE{riemann_bohm_1991, author = {K. -U. Riemann}, title = {The Bohm criterion and sheath formation}, journal = {Journal of Physics D: Applied Physics}, year = {1991}, volume = {24}, pages = {493-518}, abstract = {In the limit of a small Debye length ( lambda D to 0) the analysis of the plasma boundary layer leads to a two-scale problem of a collision free sheath and of a quasi-neutral presheath. Bohm's criterion expresses a necessary condition for the formation of a stationary sheath in front of a negative absorbing wall. The basic features of the plasma-sheath transition and their relation to the Bohm criterion are discussed and illustrated from a simple cold-ion fluid model. A rigorous kinetic analysis of the vicinity of the sheath edge allows one to generalize Bohm's criterion accounting not only for arbitrary ion and electron distributions, but also for general boundary conditions at the wall. It is shown that the generalized sheath condition is (apart from special exceptions) marginally fulfilled and related to a sheath edge field singularity. Due to this singularity, smooth matching of the presheath and sheath solutions requires an additional transition layer. Previous investigations concerning particular problems of the plasma-sheath transition are reviewed in the light of the general relations.}, doi = {10.1088/0022-3727/24/4/001}, issn = {0022-3727}, url = {http://www.iop.org/EJ/abstract/0022-3727/24/4/001} } @ARTICLE{righini_measurement_1994, author = {F. RIGHINI and J. SPISIAK and GC BUSSOLINO and A. ROSSO and J. HAIDAR}, title = {MEASUREMENT OF THERMOPHYSICAL PROPERTIES BY A PULSE-HEATING METHOD - THORIATED TUNGSTEN IN THE RANGE 1200 TO 3600 K}, journal = {INTERNATIONAL JOURNAL OF THERMOPHYSICS}, year = {1994}, volume = {15}, pages = {1311-1322}, number = {6}, month = nov, issn = {0195-928X}, keywords = {HEAT CAPACITY,resistivity,tungsten,1yr_project} } @ARTICLE{rogalski_third-generation_2009, author = {A. Rogalski and J. Antoszewski and L. Faraone}, title = {Third-generation infrared photodetector arrays}, journal = {Journal of Applied Physics}, year = {2009}, volume = {105}, pages = {091101}, number = {9}, doi = {10.1063/1.3099572}, issn = {00218979}, url = {http://link.aip.org/link/JAPIAU/v105/i9/p091101/s1&Agg=doi} } @ARTICLE{rognlien_impurity_2002, author = {T. D. Rognlien and M. E. Rensink}, title = {Impurity transport in edge plasmas with application to liquid walls}, journal = {Review,Tutorial and Invited Papers from the 43rd Annual Meeting of the APS Division of Plasma Physics}, year = {2002}, volume = {9}, pages = {2120-2126}, month = may, doi = {10.1063/1.1461384 }, keywords = {plasma boundary layers,plasma density,plasma edge,plasma impurities,plasma simulation,plasma toroidal confinement,plasma transport processes,plasma-wall interactions}, url = {http://link.aip.org/link/?PHP/9/2120/1} } @ARTICLE{rosenau_mm_wave_solid_state_devices_2000, author = {Steven A. Rosenau and Cheng Liang and Weikang Zhang and Bihe Deng and Weiying Li and Chia-Chan Chang and Pei-Ling Hsuand Richard P. Hsia and Fan Jiang and Calvin W. Domier and Neville C. Luhmann, Jr.}, title = {Millimeter Wave Solid State Devices}, journal = {Materials Research Society}, year = {2000}, pages = {AA2.1.1-12}, keywords = {millimeter waves}, owner = {erikg}, timestamp = {2009.04.01}, url = {http://www.mrs.org/s_mrs/sec_subscribe.asp?CID=2377&DID=113610&action=detail} } @ARTICLE{rosenbluth72, author = {Rosenbluth, et al.}, journal = {Physics of Fluids}, year = {1972}, volume = {15}, pages = {116}, keywords = {GPP2, neoclassical transport}, owner = {erikg}, timestamp = {2007.05.09} } @ARTICLE{rosenbluth_finite-beta_1971, author = {M. Rosenbluth and M. L. Sloan}, title = {Finite-beta Stabilization of the Collisionless Trapped Particle Instability}, journal = {Physics of Fluids}, year = {1971}, volume = {14}, pages = {1725--1741}, number = {8}, doi = {10.1063/1.1693669}, url = {http://link.aip.org/link/?PFL/14/1725/1} } @ARTICLE{rosenbluth_plasma_1972, author = {M. N. Rosenbluth and R. D. Hazeltine and F. L. Hinton}, title = {Plasma Transport in Toroidal Confinement Systems}, journal = {Physics of Fluids}, year = {1972}, volume = {15}, pages = {116--140}, number = {1}, doi = {10.1063/1.1693728}, url = {http://link.aip.org/link/?PFL/15/116/1} } @ARTICLE{rosenbluth_poloidal_1998, author = {M. N. Rosenbluth and F. L. Hinton}, title = {Poloidal Flow Driven by Ion-Temperature-Gradient Turbulence in Tokamaks}, journal = {Physical Review Letters}, year = {1998}, volume = {80}, pages = {724}, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {We show that linear collisionless processes do not damp poloidal flows driven by ion-temperature-gradient (ITG) turbulence. Since these flows play an important role in saturating the level of the turbulence, this level, as well as the transport caused by ITG modes, may be overestimated by gyrofluid simulations, which employ linear collisionless rotation damping.}, doi = {10.1103/PhysRevLett.80.724}, url = {http://link.aps.org/abstract/PRL/v80/p724} } @ARTICLE{ross_comparing_2002-1, author = {David W. Ross and Ronald V. Bravenec and William Dorland and Michael A. Beer and G. W. Hammett and George R. {McKee} and Raymond J. Fonck and Masanori Murakami and Keith H. Burrell and Gary L. Jackson and Gary M. Staebler}, title = {Comparing simulation of plasma turbulence with experiment}, journal = {Physics of Plasmas}, year = {2002}, volume = {9}, pages = {177--184}, number = {1}, doi = {10.1063/1.1424925}, keywords = {plasma density,plasma diagnostics,plasma drift waves,plasma fluctuations,plasma impurities,plasma simulation,plasma temperature,plasma toroidal confinement,plasma transport processes,plasma {turbulence,Tokamak} devices}, url = {http://link.aip.org/link/?PHP/9/177/1} } @ARTICLE{ross_comparing_2002, author = {David W. Ross and William Dorland}, title = {Comparing simulation of plasma turbulence with experiment. {II.} Gyrokinetic simulations}, journal = {Physics of Plasmas}, year = {2002}, volume = {9}, pages = {5031--5035}, number = {12}, month = dec, doi = {10.1063/1.1518997}, keywords = {plasma diagnostics,plasma fluctuations,plasma simulation,plasma temperature,plasma transport processes,plasma turbulence}, url = {http://link.aip.org/link/?PHP/9/5031/1} } @ARTICLE{ross_study_1977, author = {David W. Ross and W. M. Tang and J. C. Adam}, title = {Study of trapped electron instabilities driven by magnetic curvature drifts}, journal = {Physics of Fluids}, year = {1977}, volume = {20}, pages = {613--618}, number = {4}, month = apr, doi = {10.1063/1.861920}, keywords = {{INSTABILITY} {GROWTH} {RATES,} {ION} {COLLISIONS,} {PLASMA} {DRIFT,} {PLASMA} {MACROINSTABILITIES,} {TOKAMAK} {DEVICES,} {TRAPPEDPARTICLE} {INSTABILITY}}, url = {http://link.aip.org/link/?PFL/20/613/1} } @INPROCEEDINGS{rost_comparison_2000, author = {J.C. Rost and M. Porkolab and T.L. Rhodes and R.A. Moyer and G.R. McKee and K.H. Burrell}, title = {Comparison of Edge Fluctuation Measurements from PCI, BES, Langmuir Probes and Reflectometry on DIII-D}, booktitle = {27th EPS Conference on Controlled Fusion and Plasma Physics}, year = {2000}, volume = {24B}, series = {Europhysics Conference Abstracts}, address = {Budapest, Hungary}, month = jun, publisher = {Institute of Physics Publishing}, abstract = { Phase contrast imaging (PCI), beam emission spectroscopy (BES), reflectometry, and Langmuir probes provide different but complementary measurements of the density fluctu- ations in the edge of the DIII?D tokamak plasma. In particular, the PCI is sensitive to modes r with k? << kr, while the BES and probe response depends less on the angle of k? . On plasma discharges in which these diagnostics collect data from the same location at the same time, comparison of the signals gives more information about the turbulence than a single measurement. Comparing measurements from L? and H?mode plasma phases, we found that the L?mode frequency spectra (10?250 kHz) from BES, PCI, and reflectometry have identical shapes. However, the H?mode spectra differ significantly, with the k ? << k r modes suppressed the most. This suggests that the edge fluctuations are nearly isotropic in L?mode but highly anisotropic in H?mode. Other comparisons at the last closed flux surface in two similar low power plasma discharges differing by a factor of four in density showed power spectra with a more complicated structure.}, isbn = {9633726182}, keywords = {BES,edge fluctuations,Langmuir probes,PCI,reflectometry}, url = {http://epsppd.epfl.ch/Buda/web/contents.htm} } @ARTICLE{rost_observations_1996, author = {J. C. Rost and R. Boivin and M. Porkolab and J. Reardon and Y. Takase}, title = {Observations of Ion Edge Heating during ICRH in Alcator C-Mod}, journal = {APS Meeting Abstracts}, year = {1996}, abstract = {Observations of edge ion heating during ICRF injection on Alcator C-Mod have been made using a toroidally and poloidally scanning charge-exchange neutral particle analyzer. The phenomenon is characterized by a large flux of charge-exchange neutrals (hydrogen and deuterium), at suprathermal energies, with a short rise time (<=.2ms, the instrumental time resolution), but is not associated with impurity generation or loss of heating efficiency. Previous data showed that the RF power threshold for edge heating is decreased from 500kW to <10kW at certain values of the toroidal field. In this experiment, the energy spectra of escaping energetic neutrals were obtained for several RF power levels and particle pitch angles at three of these fields. It was found that the total energy in these suprathermal edge particles increases faster than linearly with applied RF power. Some conclusions are made about the structure of the damped field that generates the energetic ions. Supported by U.S. DOE Contract No. DE-AC02-78ET51013 }, url = {http://adsabs.harvard.edu/abs/1996APS..DPP..7R08R} } @BOOK{roth_vacuum_1990, title = {Vacuum technology}, publisher = {Elsevier Science Pub. Co.}, year = {1990}, author = {Alexander Roth}, pages = {554}, address = {New York}, edition = {Third}, keywords = {vacuum}, url = {http://catalog.princeton.edu/cgi-bin/Pwebrecon.cgi?v1=2\&ti=1,2\&Search\%5FArg=vacuum\%20technology\&Search\%5FCode=TALL\&CNT=50\&PID=q@\_FsHoIu@\_Fod\%3EJndNIt@\_Fo\%3C\%3C\%3C\&SEQ=20070131093415\&SID=8} } @ARTICLE{rutherford76, author = {P. Rutherford}, journal = {Physics of Fluids}, year = {1976}, volume = {13}, pages = {482}, keywords = {GPP2, trapped particles, ware pinch, tokamak}, owner = {Administrator}, timestamp = {2007.04.07} } @ARTICLE{rutherford_collisional_1970, author = {P. H. Rutherford}, title = {Collisional Diffusion in an Axisymmetric Torus}, journal = {Physics of Fluids}, year = {1970}, volume = {13}, pages = {482--489}, number = {2}, month = feb, doi = {10.1063/1.1692943}, keywords = {ambipolar diffusion,axisymmetric torus}, url = {http://link.aip.org/link/?PFL/13/482/1} } @ARTICLE{ryan_initial_2001, author = {P. M. Ryan and J. R. Wilson and D. W. Swain and R. I. Pinsker and M. D. Carter and D. Gates and J. C. Hosea and T. K. Mau and J. E. Menard and D. Mueller and S. A. Sabbagh and J. B. Wilgen}, title = {Initial operation of the NSTX phased array for launching high harmonic fast waves}, journal = {Fusion Engineering and Design}, year = {2001}, volume = {56-57}, pages = {569-573}, abstract = {A high harmonic fast wave (HHFW) antenna array, designed to provide up to 6 MW of power at 30 MHz for heating and current drive applications, has been operated on the NSTX experiment at Princeton Plasma Physics Laboratory (PPPL). The full array consists of 12 evenly spaced, identical current strap modules connected in pairs. Each pair is connected as a half-wave resonant loop and is intended to be driven by one transmitter, allowing rapid phase shift between transmitters. A decoupling network compensates for the mutual inductive coupling between adjacent current straps, effectively isolating the six transmitters from one another. Initial rf operation between November 1999 and January 2000 used eight straps to form four loops, which were driven by two transmitters. Two adjacent loops were connected with a [lambda]/2 coax section to be driven out of phase by a single transmitter. Up to 2 MW of power was delivered during this stage of operation; inter-loop phasings of 0-[pi]-[pi]-0 and 0-[pi]-0-[pi] were investigated. Models of the power distribution system indicate the nominal plasma loading was about 5 [Omega]/m, close to the design value of 6 [Omega]/m. The HHFW system has now been reconfigured for 12-strap, six-transmitter operation with decouplers; low power vacuum and plasma measurements have begun.}, keywords = {High harmonic fast wave (HHFW) antenna,NSTX phased array}, url = {http://www.sciencedirect.com/science/article/B6V3C-44JDTMG-31/2/0b74fc45237ad1fb529849730ab386aa} } @ARTICLE{sackschamel, author = {Sack, Ch. and Schamel, H.}, title = {Plasma Expansion into Vacuum - A Hydrodynamic Approach}, journal = {Physics Reports}, year = {1987}, volume = {156}, pages = {311-395}, number = {6}, file = {\\Docs\\plasma expansion\\sackschamel.pdf:\\Docs\\plasma expansion\\sackschamel.pdf:PDF}, keywords = {plasma expansion, 1yr_project}, owner = {egranste}, timestamp = {2007.05.16} } @ARTICLE{samir83, author = {Samir, Uri and Wright, K.H, and Stone, N.H.}, title = {The Expansion of a Plasma into a Vacuum: Basic Phenomena and Processes and Applications to Space Plasma Physics}, journal = {Reviews of Geophysics and Space Physics}, year = {1983}, volume = {21}, pages = {1631-1646}, number = {7}, file = {\\Docs\\plasma expansion\\samir83.pdf:\\Docs\\plasma expansion\\samir83.pdf:PDF}, keywords = {plasma expansion, 1yr_project}, owner = {egranste}, timestamp = {2007.05.16} } @ARTICLE{sanin_two-dimensional_2004, author = {A. L. Sanin and K. Tanaka and L. N. Vyacheslavov and K. Kawahata and T. Akiyama}, title = {Two-dimensional phase contrast interferometer for fluctuations study on {LHD}}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, pages = {3439--3441}, number = {10}, month = oct, doi = {10.1063/1.1784528}, keywords = {light interferometers,plasma confinement,plasma density,plasma diagnostics,plasma {fluctuations,Tokamak} devices}, url = {http://link.aip.org/link/?RSI/75/3439/1} } @ARTICLE{sanmartin00, author = {J.R. Sanmartin and O. Lopez-Rebollal}, title = {A new basic effect in retarding potential analyzers}, journal = {Physics of Plasmas}, year = {2000}, volume = {7}, pages = {4699-4706}, number = {11}, month = nov, file = {Docs\\Diagnostics\\Retarding Potential Analyzer\\sanmartin00.pdf:Docs\\Diagnostics\\Retarding Potential Analyzer\\sanmartin00.pdf:PDF}, keywords = {RPA, retarding potential analyzer, 1yr_project}, owner = {egranste}, timestamp = {2007.03.07} } @ARTICLE{sato_mirror_potential_1999, author = {Kunihiro SATO}, title = {Physics of Open-Field Line Plasmas. Structures of Electrostatic Potential inthe End Region of Magnetic Mirror Systems.}, journal = {Journal of Plasma and Fusion Research}, year = {1999}, volume = {75}, pages = {1180-1187}, number = {10}, note = {Article in Japanese}, abstract = {Formation of the steady-state potential in the end region of magnetic mirror systems is described. The plama-sheath equation is derived, and necessary conditions for the formation of continuous potential in nonuniform open magnetic fields are discussed on the basis of kinetic analysis. Effects of the expanding magnetic field and the ionization of neutral gas on the potential formation are studied, showing the calculated results of potential profiles in plasma flowing along open magnetic field lines.}, doi = {10.1585/jspf.75.1180}, keywords = {potential structure, potential formation end region, magnetic mirror, open magnetic field, ionization, plasma-sheath equation, necessary condition}, owner = {erikg}, timestamp = {2008.09.04}, url = {http://www.jstage.jst.go.jp/article/jspf/75/10/75_1180/_article} } @ARTICLE{sato_effects_1991, author = {Kunihiro Sato and Fujio Miyawaki}, title = {Effects of a nonuniform open magnetic field on the plasma presheath}, journal = {Physics of Fluids B: Plasma Physics}, year = {1991}, volume = {3}, pages = {1963-1967}, note = {Their calculations are only good for situations without trapping; they consider a magnetic field which weakens as it approaches a boundary.}, doi = {10.1063/1.859664}, keywords = {COLLISIONLESS PLASMA,COMPUTER CODES,CORRELATIONS,DISTRIBUTION FUNCTIONS,MAGNETIC FIELDS,MAGNETIC MIRRORS,NUMERICAL SOLUTION,PLASMA SHEATH,POTENTIALS,WALLS}, url = {http://link.aip.org/link/?PFB/3/1963/1} } @ARTICLE{sato_sheath_1989, author = {Kunihiro Sato and Fujio Miyawaki and Wakumi Fukui}, title = {Sheath and presheath in a collisionless open-field plasma}, journal = {Physics of Fluids B: Plasma Physics}, year = {1989}, volume = {1}, pages = {725-733}, month = apr, note = {Their calculations are only good for situations without trapping; they consider a magnetic field which weakens as it approaches a boundary.}, doi = {10.1063/1.859137}, keywords = {ANALYTICAL SOLUTION,COLLISIONLESS PLASMA,EQUATIONS,MAGNETIC FIELDS,PLASMA DRIFT,PLASMA SHEATH,POTENTIALS}, url = {http://link.aip.org/link/?PFB/1/725/1} } @INPROCEEDINGS{scharfe2007, author = {M.~K.~Scharfe and C.~A.~Thomas and others}, title = {Shear-Based Model for Electron Transport in 2D Hybrid Hall Thruster Simulations}, booktitle = {43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit}, year = {2007}, series = {AIAA paper 2007-5208}, address = {Cincinnati, OH}, month = {JUL}, note = {Hybrid model uses fluid electrons and pic ions. The model for the hall parameter: $\omega\tau_eff^{-1} = \omega\tau_clas^{-1} + \omega\tau_nearwall^{-1} + \omega\tau_fluc^{-1}(\frac{1}{1+(C_1s)^2})$. Here $s$ is the shear rate: $s=\frac{du_{e,\theta}}{dz}=\frac{dE_z/B_r}{dz}$ They guess values for the fit parameters to match experiment. Their model captures the experimentally-measured hall parameter better than either simply classical or Bohm models, and works well for capturing the measured plasma potential profile for 200V thruster. $T_e$ shows only a weak dependence on the fit parameters, but dependence on density is substantial, because less cross-field transport (ie. from more shear) results in lower discharge current, which means less joule heating, lower temperature, and hence ionization occurs farther from the anode.}, journal = {43rd AIAA Joint Propulsion Conference}, keywords = {shear suppression, anomalous transport, Hall thrusters, 1yr_project}, owner = {egranste}, timestamp = {2007.08.03}, url = {http://www.aiaa.org/content.cfm?pageid=413} } @ARTICLE{schmied_rate_1965, author = {H. SCHMIED and M. DEAK}, title = {RATE OF EVAPORATION OF THORIUM FROM CARBURIZED THORIATED TUNGSTEN CATHODES MEASURED BY ACTIVATION ANALYSIS}, journal = {BRITISH Journal of Applied Physics}, year = {1965}, volume = {16}, pages = {269-\&}, number = {2}, issn = {0022-3727}, keywords = {thorium,tungsten, 1yr_project} } @ARTICLE{schmitz_theory_1996, author = {H. Schmitz and K.-U. Riemann and Th. Daube}, title = {Theory of the collisional presheath in a magnetic field parallel to the wall}, journal = {Physics of Plasmas}, year = {1996}, volume = {3}, pages = {2486-2495}, month = jul, doi = {10.1063/1.871966}, keywords = {BOHM CRITERION,BOUNDARY LAYERS,COLLISIONAL PLASMA,DEBYE LENGTH,PLASMA SHEATH,SPACE CHARGE,TRANSPORT THEORY,WALL EFFECTS}, url = {http://link.aip.org/link/?PHP/3/2486/1} } @ARTICLE{schmitz_detection_2008, author = {L. Schmitz and G. Wang and J. C. Hillesheim and T. L. Rhodes and W. A. Peebles and A. E. White and L. Zeng and T. A. Carter and W. Solomon}, title = {Detection of zonal flow spectra in {DIII-D} by a dual-channel Doppler backscattering system}, journal = {Review of Scientific Instruments}, year = {2008}, volume = {79}, pages = {{10F113}}, number = {10}, doi = {10.1063/1.2953675}, issn = {00346748}, url = {http://link.aip.org/link/RSINAK/v79/i10/p10F113/s1&Agg=doi} } @ARTICLE{schnack_computational_2006, author = {D. D. Schnack and D. C. Barnes and D. P. Brennan and C. C. Hegna and E. Held and C. C. Kim and S. E. Kruger and A. Y. Pankin and C. R. Sovinec}, title = {Computational modeling of fully ionized magnetized plasmas using the fluid approximation}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {058103-21}, month = may, keywords = {numerical analysis,plasma kinetic theory,plasma simulation}, url = {http://link.aip.org/link/?PHP/13/058103/1} } @BOOK{schnars_digital_2005, title = {Digital Holography: Digital Hologram Recording, Numerical Reconstruction, and Related Techniques}, publisher = {Springer}, year = {2005}, author = {Ulf Schnars and Werner P Jueptner}, pages = {164}, address = {Berlin}, isbn = {354021934X}, keywords = {Holography} } @ARTICLE{schwager_effects_1993, author = {L. A. Schwager}, title = {Effects of secondary and thermionic electron emission on the collector and source sheaths of a finite ion temperature plasma using kinetic theory and numerical simulation}, journal = {Physics of Fluids B: Plasma Physics}, year = {1993}, volume = {5}, pages = {631-645}, month = feb, keywords = {1yr\_project,2yr\_project,BEAMPLASMA SYSTEMS,ELECTRON EMISSION,KINETIC EQUATIONS,PLASMA SHEATH,PLASMA SIMULATION,PLASMA SOURCES,PLASMAWALL INTERACTIONS,THERMIONIC EMISSION,TRANSPORT THEORY,WALL EFFECTS}, url = {http://link.aip.org/link/?PFB/5/631/1} } @ARTICLE{semenov_phenomenology_2003, author = {I. Semenov and S. Mirnov and D. Darrow and L. Roquemore and E. D. Fredrickson and J. Menard and D. Stutman and A. Belov}, title = {Phenomenology of internal reconnections in the National Spherical Torus Experiment}, journal = {Physics of Plasmas}, year = {2003}, volume = {10}, pages = {664-670}, month = mar, doi = {10.1063/1.1539031}, keywords = {fusion reactor theory,internal reconnection event,plasma instability,plasma magnetohydrodynamics,plasma toroidal confinement,plasma transport processes,Tokamak devices}, url = {http://link.aip.org/link/?PHP/10/664/1} } @ARTICLE{semenov_modeling_1999, author = {V. E. Semenov and A. N. Smirnov and A. Turlapov}, title = {Modeling of a mirror-trapped plasma for an ECR ion source}, journal = {FUSION TECHNOLOGY}, year = {1999}, volume = {35}, pages = {398-402}, abstract = {A new model is developed for an electron-cyclotron-resonance-heated plasma confinement in an open mirror magnetic trap. The model is based on the simultaneous study of noncollisional kinetics of electrons and gas dynamics of ions. At the trap center, the electron distribution function is approximated by bi-Maxwell distribution (with effective temperatures T-perpendicular to and T-parallel to - mean energies of the transverse and longitudinal to the magnetic field motion). Within the model framework the ion confinement time as well as the axial distribution of the ambipolar potential and plasma density has been investigated both numerically and analytically. The confinement time and potential profile are very much dependent on the electron distribution anisotropy and, in strongly anisotropic case, on the ion temperature. The ambipolar potential changes qualitatively while the ratio T-perpendicular to/T-parallel to exceeds a certain threshold value. Below the threshold, the potential falls off monotonously along the trap axis outwards fi om the trap center. After the threshold is exceeded, there appears a potential peak between the center and the plug. This potential peak retards ion escape through the plug and provides quite different confinement of ions with different charges hn an ECR ion source.}, issn = {0748-1896} } @ARTICLE{1997APS..DPPhTO113S, author = {{Semenov}, V.~E. and {Turlapov}, A.}, title = {{Confinement of an electron cyclotron resonance heated mirror plasma}}, journal = {APS Meeting Abstracts}, year = {1997}, pages = {113-+}, month = nov, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1997APS..DPPhTO113S}, keywords = {mirrors, open systems, 2yr_project} } @ARTICLE{sharma_kinetic_2005, author = {Devendra Sharma}, title = {Kinetic Lagrange simulation of a source-driven magnetized oblique presheath}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {103506-11}, month = oct, doi = {10.1063/1.2098367}, keywords = {plasma density,plasma flow,plasma kinetic theory,plasma sheaths,plasma simulation,plasma sources,plasma temperature}, url = {http://link.aip.org/link/?PHP/12/103506/1} } @ARTICLE{1977JPhD...10..355S, author = {{Sherman}, J.~C.}, title = {{Secondary electron emission by multiply charged ions and its magnitude in vacuum arcs }}, journal = {Journal of Physics D Applied Physics}, year = {1977}, volume = {10}, pages = {355-359}, month = feb, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1977JPhD...10..355S}, keywords = {secondary electron emission, 1yr_project} } @ARTICLE{shevchenko_development_2007, author = { V Shevchenko and G Cunningham and A Gurchenko and E Gusakov and B Lloyd and M {O'Brien} and A Saveliev and A Surkov and F Volpe and M Walsha}, title = {Development of Electron Bernstein wave research in Mast}, journal = {{FUSION} {SCIENCE} {AND} {TECHNOLOGY}}, year = {2007}, volume = {52}, pages = {202--215}, number = {2}, month = aug, note = {{EBW,} {RF} heating, emission}, abstract = {Burning plasma spherical tokamaks {(STs)} rely on off-axis current drive {(CD)} and nonsolenoid start-up techniques. Electron Bernstein waves {(EBWs)} may provide efficient off-axis heating and {CD} in high-density {ST} plasmas. {EBWs} may also be used in the plasma start-up phase because {EBW} absorption and {CD} efficiency remain high even in relatively cold plasmas. {EBW} studies on the Mega Ampere Spherical Tokamak {(MAST)} can be subdivided into four separate subjects: thermal electron cyclotron emission observations from overdense plasmas, {EBW} modeling, proof-of-principle {EBW} heating experiments with the existing {60-GHz} gyrotrons, and {EBW} assisted plasma start-up at 28 {GHZ.} These studies are also aimed at determining the potential for a high-power {EBW} system for heating and {CD} in {MAST} The optimum choice of frequency and launch configuration is a key issue for future applications in {MAST} This paper describes diagnostics, modeling tools, and high-power radio frequency systems developed specifically for {EBW} research in {MAST} The experimental methodology employed in proof-of-principle {EBW} heating experiments along with experimental results is discussed in detail. {EBW} heating via the {ordinary-extraordinary-Bernstein} {(O-X-B)} mode conversion has clearly been observed for the first time in an {ST.}}, issn = {1536-1055}, url = {http://epubs.ans.org/?a=1499} } @ARTICLE{shih_secondary_1993, author = {A. Shih and C. Hor}, title = {Secondary emission properties as a function of the electron incidence angle}, journal = {Electron Devices, IEEE Transactions on}, year = {1993}, volume = {40}, pages = {824-829}, abstract = {Computer codes being developed to improve the understanding of crossed-field amplifier (CFA) performance require a more complete and reliable database of the secondary electron emission properties of the electrode materials than exists in the literature. The authors describe an experimental method and present results of secondary emission yield measurements on molybdenum surfaces, both clean and gas-exposed. The surface cleanliness was monitored by Auger electron spectroscopy (AES), and all measurements were made under ultrahigh-vacuum conditions (better than 1?10-10 torr). The results differ from the existing data for which the surface cleanliness was not determined. The secondary electron emission yields were measured as a function of the primary electron energy and also of the angle of incidence. The results were fitted with the analytical expressions of J.R.M. Vaughan (1989), with good overall agreement if Vaughan's formulas are slightly modified }, doi = {10.1109/16.202797}, issn = {0018-9383}, keywords = {Auger electron spectroscopy,crossed-field amplifier,electrode materials,electron incidence angle,secondary electron emission,secondary electron emission properties,secondary electron emission yields,secondary emission yield measurements,surface cleanliness} } @ARTICLE{shirasaki_operational_2007, author = {Atsushi Shirasaki and Hirokazu Tahara}, title = {Operational characteristics and plasma measurements in cylindrical Hall thrusters}, journal = {Journal of Applied Physics}, year = {2007}, volume = {101}, pages = {073307-7}, month = apr, keywords = {aerospace propulsion,ionisation,plasma accelerators,plasma magnetohydrodynamics,plasma probes}, url = {http://link.aip.org/link/?JAP/101/073307/1} } @ARTICLE{simon_ambipolar_1955, author = {Albert Simon}, title = {Ambipolar Diffusion in a Magnetic Field}, journal = {Physical Review}, year = {1955}, volume = {98}, pages = {317}, number = {2}, month = apr, note = {Copyright {(C)} 2009 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {Diffusion of ions in a plasma across a magnetic field is shown to be not ambipolar in character in most arc experiments. Owing to the highly anisotropic conductivity of the medium, the ions diffuse across the field at their own intrinsic rate. Space-charge neutralization is maintained by slight adjustments of the currents in the direction of the magnetic field lines. The discrepancy between theory and experiment noted by Bohm is thus resolved and no additional mechanisms, such as plasma oscillations, need be postulated.}, doi = {10.1103/PhysRev.98.317}, url = {http://link.aps.org/abstract/PR/v98/p317} } @INCOLLECTION{sivukhin1970energy, author = {Sivukhin, V.~D.}, title = {Energy Balance and the Feasibility of a Self-Sustaining Thermonuclear Reaction in a Mirror Device}, booktitle = {Reviews of Plasma Physics}, publisher = {Consultants Bureau}, year = {1970}, editor = {Leontovich, M.~A.}, volume = {5}, pages = {497--525}, address = {New York}, keywords = {mirrors, open systems, 2yr_project}, owner = {erikg}, timestamp = {2007.12.06} } @ARTICLE{smirnov_electron_2006, author = {A.N. Smirnov and Y. Raitses and N.J. Fisch}, title = {Electron cross-field transport in a miniaturized cylindrical Hall thruster}, journal = {IEEE Transactions on Plasma Science}, year = {2006}, volume = {34}, pages = {132-141}, number = {2.1}, month = {APR}, doi = {10.1109/TPS.2006.872185}, keywords = {Bohm diffusion, anomalous transport,electron cross-field transport,electron transport,electron-wall collisions,Langmuir probes, Hall thruster,plasma-wall interactions,1yr_project}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=33960&arnumber=1621281&count=14&index=0} } @ARTICLE{smirnov_experimental_2007, author = {Artem Smirnov and Yegeny Raitses and Nathaniel J. Fisch}, title = {Experimental and theoretical studies of cylindrical Hall thrusters}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {057106}, number = {5}, eid = {057106}, doi = {10.1063/1.2718522}, keywords = {ionization; plasma-wall interactions; plasma probes; plasma fluctuations; Hall thruster, 1yr_project}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/14/057106/1} } @ARTICLE{smirnov_enhanced_2003, author = {A. Smirnov and Y. Raitses and N. J. Fisch}, title = {Enhanced ionization in the cylindrical Hall thruster}, journal = {Journal of Applied Physics}, year = {2003}, volume = {94}, pages = {852-857}, month = jul, keywords = {ionisation,plasma devices,plasma magnetohydrodynamics,plasma simulation,plasma-wall interactions,propulsion}, url = {http://link.aip.org/link/?JAP/94/852/1} } @CONFERENCE{smirnov_iepc_2003, author = {A. Smirnov and Y. Raitses and N. J. Fisch}, title = {Enhanced Ionization in the Cylindrical Hall Thruster}, booktitle = {IEPC paper 2003-156}, year = {2003}, address = {Toulouse, France}, month = mar, organization = {International Electric Propulsion Conference}, note = {CHT has high propellant utilization (ionization efficiency). A quasi-1D model shows that reduction in wall losses alone due to cylindrical vs. annular geometry is insufficient to explain the increase. Both the 9cm and 2.6cm CHT can operate at lower flow rates than possible in annular configurations. Propellant utilization for the 9cm thruster is $\sim 0.8$ from 200-300V, but on the 2.6cm, it increases from 0.8--1.1 indicating doubly-charged ions. Why is it higher for the smaller thruster? I would expect smaller volume-surface ratio would correspond with greater wall losses and decreased propellant utilization. He also claims that the anomalous electron mobility should be smaller in the CHT, because the radial B field is 1.5-2 times larger than in the annular case. I thought the radial B field was smaller in the CHT. His theory is that this leads to increased electron density (say a factor of two) to get a 25\% increase in propellant utilization. In his quasi-1D model, space-charge saturation of the wall sheath limits electron energy losses (the SEE is capped at a critical vaue, and the potential drop between the plasma and the minimum of the sheath potential well is about $T_e$). This limits the electron temperature at a threshold value, and since the SEE coefficient is a function of wall material and electron temperature, the maximum electron temperature is influenced strongly by the thruster channel material.}, keywords = {hall thruster, CHT, ionization, SEE, sheath, 1yr_project}, owner = {egranste}, timestamp = {2007.06.22} } @ARTICLE{smirnov_parametric_2002, author = {A. Smirnov and Y. Raitses and N. J. Fisch}, title = {Parametric investigation of miniaturized cylindrical and annular Hall thrusters}, journal = {Journal of Applied Physics}, year = {2002}, volume = {92}, pages = {5673-5679}, month = nov, keywords = {aerospace propulsion,electric propulsion,plasma devices}, url = {http://link.aip.org/link/?JAP/92/5673/1} } @INPROCEEDINGS{smirnov_em_wave_beam_propagation_1999, author = {Smirnov, A.~I. and Petrov, E.~Yu.}, title = {Electromagnetic Wave Beams in an Inhomogeneous Magnetoplasma}, booktitle = {26th EPS Conference on Controlled Fusion and Plasma Physics}, year = {1999}, number = {v. 23J}, series = {Europhysics conference abstracts}, pages = {1797--1800}, month = {JUN}, publisher = {European Physical Society}, keywords = {electromagnetic wave propagation, optics}, owner = {erikg}, timestamp = {2008.07.31}, url = {http://epsppd.epfl.ch/Maas/web/cross/p4113.htm} } @PHDTHESIS{smirnov_experimental_thesis_2006, author = {Artem N. Smirnov}, title = {Experimental and Theoretical Studies of Cylindrical Hall Thrusters}, school = {Princeton University}, year = {2006}, month = {SEP}, keywords = {Hall thruster, 1yr_project}, owner = {egranste}, timestamp = {2007.11.05} } @ARTICLE{smith_microwave_2004, author = {D. R. Smith and E. Mazzucato and T. Munsat and H. Park and D. Johnson and L. Lin and C. W. Domier and M. Johnson and Jr. Luhmann}, title = {Microwave scattering system design for rho[sub e] scale turbulence measurements on NSTX}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, pages = {3840-3842}, month = oct, note = {From 2008 APS DPP talk, measured significant signals up to about 7.5MHz. Spatial localization about 10cm along the path length, about 2.5 cm radial.}, doi = {10.1063/1.1788851}, keywords = {microwave detectors,plasma diagnostics,plasma fluctuations,plasma toroidal confinement,plasma transport processes,plasma turbulence,Tokamak devices}, url = {http://link.aip.org/link/?RSI/75/3840/1} } @ARTICLE{smith_stochastic_1975, author = {Gary R. Smith and Allan N. Kaufman}, title = {Stochastic Acceleration by a Single Wave in a Magnetic Field}, journal = {Physical Review Letters}, year = {1975}, volume = {34}, pages = {1613}, month = jun, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {The nature of a particle orbit in an electrostatic plasma wave is modified by a magnetostatic field, because there exists a set of resonant parallel velocities (?+l?) / kz. If the wave amplitude ?0 is sufficiently large, neighboring resonant regions overlap, and the particle motion becomes stochastic; the threshold condition is kz2(e / m)?0|Jl(k??)|??2 / 16. As an application, a weakly damped intermediate-frequency ion-acoustic wave may be used to heat the tail of an ion distribution.}, doi = {10.1103/PhysRevLett.34.1613}, keywords = {nonlinear processes}, url = {http://link.aps.org/abstract/PRL/v34/p1613} } @BOOK{smythe_static_1967, title = {Static and Dynamic Electricity}, publisher = {{McGraw-Hill}}, year = {1967}, author = {William Ralph Smythe}, pages = {623}, series = {International series in pure and applied physics}, address = {New York}, edition = {3d ed}, keywords = {{Electrodynamics,Electrostatics}}, lccn = {{QC518} {.S55} 1968} } @ARTICLE{snyder_edge_2002, author = {P. B. Snyder and H. R. Wilson and J. R. Ferron and L. L. Lao and A. W. Leonard and T. H. Osborne and A. D. Turnbull and D. Mossessian and M. Murakami and X. Q. Xu}, title = {Edge localized modes and the pedestal: A model based on coupled peeling--ballooning modes}, journal = {Review,Tutorial and Invited Papers from the 43rd Annual Meeting of the APS Division of Plasma Physics}, year = {2002}, volume = {9}, pages = {2037-2043}, month = may, doi = {10.1063/1.1449463 }, keywords = {ballooning instability,plasma instability,plasma magnetohydrodynamics,plasma toroidal confinement,Tokamak devices}, url = {http://link.aip.org/link/?PHP/9/2037/1} } @INPROCEEDINGS{sommerville_effect_2007, author = {J.~D. Sommerville and L.~B. King}, title = {Effect of Cathode Position on Hall-Effect Thruster Performance and Cathode Coupling Voltage}, booktitle = {30th International Electric Propulsion Conference}, year = {2007}, series = {IEPC paper 2007-78}, address = {Florence, Italy}, month = {SEP}, keywords = {1yr_project, Hall Thruster}, owner = {erikg}, timestamp = {2008.03.03}, url = {http://www.me.mtu.edu/researchAreas/isp/publications.html} } @PHDTHESIS{soukhanovskii_impurity_2001, author = {Vsevolod A. Soukhanovskii}, title = {Impurity transport study in the low aspect ratio tokamak {CDX-U} based on vacuum ultraviolet spectroscopy}, school = {The Johns Hopkins University}, year = {2001}, note = {{Ph.D.}}, abstract = {Vacuum ultraviolet spectroscopy has been used to study intrinsic impurity transport in the low aspect ratio tokamak {CDX-U.} In this context, several novel spectroscopic diagnostics have been developed and successfully operated. A class of compact stacked grid collimator-based grating instruments has been designed for impurity characterization in the boundary fusion plasmas. The C IV $\lambda$ = 1550 Angstroms monochromator prototype of the instrument has been built, radiometrically calibrated and operated on {CDX-U.} Other upgrades to {CDX-U} spectroscopic diagnostics include visible and extreme ultraviolet spectrometers and two ten channel {AXUV} diode arrays. The poloidal multilayer mirror array measures the 0 {VI} $\lambda$ = 150 Angstroms brightness profile, whereas the tangential foil filter array measures radiated power, 0 {VI} or C V brightness profiles. In combination with {CDX-U} temperature, density and magnetic measurements the spectroscopic diagnostics have been used for plasma regime characterization, investigation of the impact of the magnetohydrodynamic {(MHD)} activity on impurity profiles and the steady-state low Z impurity transport studies. {MHD-dominated} and quiescent ohmic hydrogen as well as ohmic and high harmonic fast wave heated deuterium plasmas with $T_e \leq 80$ {eV,} $\bar{n_e}\sim (0.6-3) \times 10^{13} \mathrm{cm}^{-3}$ and $Z_{eff}\sim 1.5-3$ have been studied. The {MHD} instabilities observed in {CDX-U} are the low n / m modes, the sawtooth oscillations and the internal reconnection events. The range of possible impurity diffusion coefficients D and convection velocities v has been inferred from time-dependent numerical simulations of impurity emissivity profiles. The estimated values are $0.2\mathrm{m}^2/\mathrm{s}\leq D \leq 0.6 \mathrm{m}^2/\mathrm{s} and v \leq 10$ m/s. One dimensional transport code {MIST} and the collisional-radiative package {CRMLIN} have been used. Analytical predictions of the neoclassical impurity transport theory give $D\leq 20\mathrm{m}^2/\mathrm{s}$ and $v\leq 500 $m/s. The neoclassical v / D ratio is close to the measured ratio. The calculated impurity profiles are more peaked than the measured. The peaked impurity distributions in {CDX-U} are the result of large ion density and temperature gradients. The applicability of the neoclassical theory of impurity transport developed for large aspect ratio high field circular cross-section tokamaks to the small aspect ratio low field {CDX-U} tokamak is discussed.}, file = {soukhanovskii_impurity_2001.pdf:refs/theses/soukhanovskii_impurity_2001.pdf:PDF}, keywords = {Atoms \& subatomic {particles,Fluid} {dynamics,Gases}}, url = {http://proquest.umi.com/pqdweb?did=728106851&Fmt=7&clientId=17210&RQT=309&VName=PQD} } @ARTICLE{soukhanovskii_observation_2002, author = {V. A. Soukhanovskii and M. Finkenthal and H. W. Moos and D. Stutman and T. Munsat and B. Jones and D. Hoffman and R. Kaita and R. Majeski}, title = {Observation of neoclassical impurity transport in Ohmically heated plasmas of {CDX-U} low aspect ratio tokamak}, journal = {Plasma Physics and Controlled Fusion}, year = {2002}, volume = {44}, pages = {2339--2355}, number = {11}, abstract = {High b, good confinement and stability properties of the low aspect ratio tokamaks, or spherical tori {(ST),} have been predicted theoretically and preliminarily confirmed in several large experiments recently. This paper reports on impurity transport experiments carried out in ohmically heated plasmas of the small spherical torus {CDX-U} with the aspect ratio of A[?]1.5. Vacuum ultraviolet and soft x-ray multichannel spectroscopic diagnostics are used to measure intrinsic carbon, oxygen and radiated power radial brightness profiles in plasmas with Te(0)[?]60-80 {eV} and ne(0)[?]2x1013 cm[?]3. The measurements are performed in both magnetohydrodynamically dominated and quiescent phase of the plasmas. The properties of the observed low m/n modes, sawtooth oscillations, and {ST-specific} reconnection events are discussed in the context of particle transport. The measured impurity profiles are modelled using one-dimensional impurity transport code {MIST} and a collisional-radiative package {CRMLIN.} Impurity diffusion of 0.2 m2 s[?]1[?] D[?] 0.6 m2 s[?]1 and convection velocity of v[?]4-6 m s[?]1 are inferred from the modelling. These transport coefficients are very close to the neoclassical theory predictions obtained with the {FORCEBAL} code, which uses analytical plasma viscosity expressions valid for an arbitrary aspect ratio geometry. Neoclassical analysis indicates that both carbon and oxygen are in the collisional regime, and the {Pfirsch-Schluter} flux is the major fraction of the impurity flux. The causes of the observed strong non-diffusive transport are discussed, and it is concluded that the [?]ni/ni term, resulting from highly peaked ion density profile, makes the largest contribution to the inward pinch. Present analysis suggests that drift wave turbulence is reduced in {CDX-U} ohmically heated discharges within at least r/a[?] 0.4, however more refined measurements are needed to interpret the results in the framework of {ST} ion transport.}, issn = {0741-3335}, url = {http://www.iop.org/EJ/abstract/0741-3335/44/11/304} } @ARTICLE{soukhanovskii_multilayer_2001, author = {V. A. Soukhanovskii and D. Stutman and M. Iovea and M. Finkenthal and H. W. Moos and T. Munsat and B. Jones and D. Hoffman and R. Kaita and R. Majeski}, title = {Multilayer mirror and foil filter AXUV diode arrays on CDX-U spherical torus}, journal = {Papers from the thirteenth topical conference on high temperature plasma diagnostics}, year = {2001}, volume = {72}, pages = {737--741}, doi = {10.1063/1.1323254}, keywords = {kink instability,mirrors,optical filters,optical multilayers,photodiodes,plasma diagnostics,plasma impurities,plasma toroidal confinement,sawtooth instability, Tokamak, ultraviolet detectors, X-ray detection,X-ray imaging,X-ray optics}, url = {http://link.aip.org/link/?RSI/72/737/1} } @ARTICLE{spawr_metal_1976, author = {W. J. Spawr and R. L. Pierce}, title = {Metal mirror selection guide}, journal = {Optics \& Laser Technology}, year = {1976}, volume = {8}, pages = {25--30}, number = {1}, month = feb, abstract = {Several pertinent parameters are frequently overlooked in specifying metal mirrors for high energy laser systems. This report outlines the importance of those parameters and describes both the typical and the state-of-the-art characteristics presently available.}, doi = {10.1016/0030-3992(76)90084-0}, issn = {0030-3992}, url = {http://www.sciencedirect.com/science/article/B6V4H-46G2WRN-9/2/ea819435b97d1f717b6c76249924eb1d} } @ARTICLE{spizzo_chaos_2007, author = {G. Spizzo and R. B. White and S. Cappello}, title = {Chaos generated pinch effect in toroidal confinement devices}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {102310-8}, month = oct, url = {http://link.aip.org/link/?PHP/14/102310/1} } @CONFERENCE{staack_control_2003, author = {D. Staack and Y. Raitses and N. J. Fisch}, title = {Control of Acceleration Region in Hall Thrusters}, booktitle = {IEPC paper 03-0273}, year = {2003}, address = {Toulouse, France}, month = mar, organization = {International Electric Propulsion Conference}, note = {Biasing an inner graphite electrode and a floating outer graphite electrode near the thruster channel exit shifts the acceleration region towards the anode. These graphite electrodes also cause an increase in discharge current, because the electrodes act as ``parallel resistors'' through which additional current can flow.}, keywords = {Hall thruster, 1yr_project}, owner = {egranste}, timestamp = {2007.06.22} } @ARTICLE{staebler_theory-based_2007, author = {G. M. Staebler and J. E. Kinsey and R. E. Waltz}, title = {A theory-based transport model with comprehensive physics}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {055909--7}, number = {5}, month = may, doi = {10.1063/1.2436852}, keywords = {drift instability, plasma collision processes, plasma drift waves, plasma impurities, plasma kinetic theory, plasma nonlinear processes, plasma simulation, plasma temperature, plasma toroidal confinement, plasma transport processes, plasma turbulence, Tokamak devices}, url = {http://link.aip.org/link/?PHP/14/055909/1} } @ARTICLE{stoltz_numerical_, author = {P. H. Stoltz and P. Tech-X Corporation, 5541 Central Avenue, Suite 135, Boulder, Colorado 80301, USA}, title = {Numerical simulation of the generation of secondary electrons in the High Current Experiment}, journal = {Physical Review Special Topics - Accelerators and Beams}, volume = {6}, pages = {054701}, doi = {10.1103/PhysRevSTAB.6.054701 }, url = {http://link.aps.org/abstract/PRSTAB/v6/e054701} } @ARTICLE{strachan_supershots_1992, author = {J.D. Strachan and M. Bell and A. Janos and S. Kaye and S. Kilpatrick and D. Manos and D. Mansfield and D. Mueller and K. Owens and C.S. Pitcher and J. Snipes and J. Timberlake}, title = {Experiments on TFTR supershot plasmas}, journal = {Journal of Nuclear Materials}, year = {1992}, volume = {196-198}, pages = {28 - 34}, note = {Plasma-Surface Interactions in Controlled Fusion Devices, Proceedings of the Tenth International Conference on Plasma-Surface Interactions in Controlled Fusion Devices}, doi = {DOI: 10.1016/S0022-3115(06)80008-5}, issn = {0022-3115}, url = {http://www.sciencedirect.com/science/article/B6TXN-4PRFR1J-7/2/4accf7449c934a12ed681e9a35189676} } @ARTICLE{strachan_high-temperature_1987, author = {J. D. Strachan and M. Bitter and A. T. Ramsey and M. C. Zarnstorff and V. Arunasalam and M. G. Bell and N. L. Bretz and R. Budny and C. E. Bush and S. L. Davis and H. F. Dylla and P. C. Efthimion and R. J. Fonck and E. Fredrickson and H. P. Furth and R. J. Goldston and L. R. Grisham and B. Grek and R. J. Hawryluk and W. W. Heidbrink and H. W. Hendel and K. W. Hill and H. Hsuan and K. P. Jaehnig and D. L. Jassby and F. Jobes and D. W. Johnson}, title = {High-temperature plasmas in a tokamak fusion test reactor}, journal = {Physical Review Letters}, year = {1987}, volume = {58}, pages = {1004}, number = {10}, month = mar, note = {TFTR, supershot}, abstract = {Neutral-beam heating of plasmas in the Tokamak Fusion Test Reactor at low preinjection densities [$n_e(0)=10^{19}$ m-3] were characterized by Te(0)=6.5 {keV,} Ti(0)=20 {keV,} $ne(0)=7\times10^{19}$ m-3, {$\tau_E$=170} msec, $\beta_\theta$=2, and a {d(d,n)3He} neutron emission rate of 1016 sec-1. The ion temperature and the deuterium-fusion neutron yields were significantly higher than for previous tokamak experiments. The low initial densities were achieved by operation of the Tokamak Fusion Test Reactor with low plasma currents ($\lesseq$1 {MA)} and by extensive limiter conditioning.}, doi = {{10.1103/PhysRevLett.58.1004}}, url = {http://link.aps.org/abstract/PRL/v58/p1004} } @INPROCEEDINGS{strickler_thomson_2008, author = {T. Strickler and R. Majeski and R. Kaita and B. {LeBlanc}}, title = {The Thomson scattering system on the lithium tokamak experiment}, booktitle = {Rev. Sci. Instrum.}, year = {2008}, volume = {79}, pages = {10E738--5}, month = oct, publisher = {{AIP}}, doi = {10.1063/1.2955576}, keywords = {lithium,ltx,plasma confinement,plasma density,plasma diagnostics,plasma {temperature,Tokamak} devices}, url = {http://link.aip.org/link/?RSI/79/10E738/1} } @ARTICLE{stutman_line_1997, author = {D. Stutman and J. Menard and Y. S. Hwang and W. Choe and M. Ono and M. Finkenthal and V. Soukhanovskii and M. J. May and S. P. Regan and H. W. Moos}, title = {Line emission tomography for {CDX-U} using filtered diodes}, journal = {Proceedings of the eleventh topical conference on high temperature plasma diagnostics}, year = {1997}, volume = {68}, pages = {1059--1062}, doi = {10.1063/1.1147787}, keywords = {band-pass filters, {CARBON} {IONS,} {ELECTRON} {SPECTRA,} {ELECTRON} {TEMPERATURE,} {EMISSION} {SPECTRA,} {EXTREME} {ULTRAVIOLET} {SPECTRA,} image reconstruction, {IMPURITIES,} {MAGNETOHYDRODYNAMICS,} optical tomography, {PALLADIUM,} photodiodes, plasma boundary layers, {PLASMA} {DIAGNOSTICS,} plasma magnetohydrodynamics, plasma toroidal confinement, {SILVER,} {TOKAMAK} {DEVICES,} {TOMOGRAPHY,} ultraviolet detectors, X {RADIATION,} {ZIRCONIUM}}, url = {http://link.aip.org/link/?RSI/68/1059/1} } @ARTICLE{su_plasma_1990, author = {J. J. Su and T. Katsouleas and J. M. Dawson and R. Fedele}, title = {Plasma lenses for focusing particle beams}, journal = {Physical Review A}, year = {1990}, volume = {41}, pages = {3321}, month = mar, note = {Copyright (C) 2008 The American Physical Society; Please report any problems to prola@aps.org}, abstract = {The focusing of particles by a thin plasma lens is analyzed with physical, linearized fluid and particle-in-cell computational models. For parameters similar to next-generation linear colliders, the plasma lens strength can exceed 100 MG/cm, and the luminosity can be enhanced by an order of magnitude by passing each beam through an appropriate plasma slab. The plasma electrons affect the focusing by shifting so as to (partially or completely) charge neutralize the beam. Both overdense and underdense plasma lenses are described (plasma density n0 greater or less than beam density nb). The former case applies equally well to e+ and e- beams, while the latter has distinct advantages for e- beams (including smaller aberrations and background). The effects of spherical and longitudinal aberrations, emittance, plasma boundaries, and non-linear-plasma dynamics on the final spot size are discussed.}, doi = {10.1103/PhysRevA.41.3321}, url = {http://link.aps.org/abstract/PRA/v41/p3321} } @ARTICLE{sydorenko_plasma-sheath_2008, author = {D. Sydorenko and A. Smolyakov and I. Kaganovich and Y. Raitses}, title = {Plasma-sheath instability in Hall thrusters due to periodic modulation of the energy of secondary electrons in cyclotron motion}, journal = {Physics of Plasmas}, year = {2008}, volume = {15}, pages = {053506-7}, month = may, doi = {10.1063/1.2918333}, keywords = {cyclotrons,plasma accelerators,plasma-beam interactions,plasma instability,plasma sheaths,plasma simulation}, url = {http://link.aip.org/link/?PHP/15/053506/1} } @ARTICLE{sydorenko_effects_2007, author = {D. Sydorenko and A. Smolyakov and I. Kaganovich and Y. Raitses}, title = {Effects of non-Maxwellian electron velocity distribution function on two-stream instability in low-pressure discharges}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {013508-8}, doi = {10.1063/1.2435315}, keywords = {electron beams,plasma beam injection heating,plasma instability,plasma magnetohydrodynamics,plasma sheaths,plasma simulation,plasma transport processes,plasma-wall interactions,secondary electron emission}, url = {http://link.aip.org/link/?PHP/14/013508/1} } @ARTICLE{sydorenko_modification_2006, author = {D. Sydorenko and A. Smolyakov and I. Kaganovich and Y. Raitses}, title = {Modification of electron velocity distribution in bounded plasmas by secondary electron emission}, journal = {IEEE Transactions on Plasma Science}, year = {2006}, volume = {34}, pages = {815-824}, month = jun, abstract = {A particle-in-cell code has been developed for simulations of plasmas of Hall thruster discharges. The simulated system is a plasma slab bounded by dielectric walls with secondary electron emission. An external, accelerating electric field directed parallel to the walls and an external magnetic field directed normal to the walls are applied. The strongly anisotropic non-Maxwellian electron velocity distribution function is obtained in simulations. The average energy of electron motion parallel to the walls is defined by collisional heating in. the accelerating electric field. This energy is much higher than the average energy of electron motion normal to the walls, which is determined by the energy of electrons produced in ionization and by scattering of electrons by neutral atoms. The electron distribution function for velocity components normal to the walls is depleted for energies above the near-wall plasma potential. The effects of Coulomb collisions on the electron velocity distribution function and electron wall losses are studied.}, issn = {0093-3813}, keywords = {ARGON,COULOMB COLLISIONS,electron beams,electron emission,ENERGY DISTRIBUTION,Hall effect,HALL THRUSTER,MODEL,NEAR-WALL,particle collisions,Physics, Fluids \& Plasmas,plasma engines,plasma sheaths,RF DISCHARGE,SIMULATION,TRANSITION,WALL CONDUCTIVITY} } @ARTICLE{sykes_first_1992, author = {A. Sykes and E. Del Bosco and R.J. Colchin and G. Cunningham and R. Duck and T. Edlington and D.H.J. Goodall and M.P. Gryaznevich and J. Holt and J. Hugill and J. Li and S.J. Manhood and B.J. Parham and D.C. Robinson and T.N. Todd and M.F. Turner}, title = {First results from the START experiment}, journal = {Nuclear Fusion}, year = {1992}, volume = {32}, pages = {694-699}, abstract = {Low aspect ratio tokamaks may provide a low cost route to developing magnetic fusion energy and may offer simpler and more economic fusion reactors. The first test of this concept with hot plasmas has been conducted with the Small Tight Aspect Ratio Tokamak (START) experiment now in operation at Culham Laboratory. The novel method of plasma formation is described and observations of plasmas at aspect ratios as low as 1.3 are presented, indicating high temperature discharges with good global stability properties and typical tokamak characteristics. This represents a new and significant extension of the parameter range of the conventional tokamak}, doi = {10.1088/0029-5515/32/4/I16}, issn = {0029-5515}, keywords = {spherical torus,ST,START}, url = {http://www.iop.org/EJ/abstract/0029-5515/32/4/I16/} } @ARTICLE{hahm2000, author = {T S Hahm, K H Burrell, Z Lin, R Nazikian and E J Synakowski}, title = {Zonal flow measurements concept I}, journal = {Plasma Physics and Controlled Fusion}, year = {2000}, volume = {42}, pages = {A205-A210}, number = {5A}, abstract = {We study the characteristics of self-generated zonal flows as observed in nonlinear global gyrokinetic simulations of toroidal ion temperature gradient (ITG) turbulence for typical parameters of DIII-D core plasmas. In addition, we discuss various possibilities for experimental measurements and the development of new diagnostics.}, url = {http://stacks.iop.org/0741-3335/42/A205} } @ARTICLE{takahashi_scrape-off-layer_2008, author = {Hironori Takahashi and E. D. Fredrickson and M. J. Schaffer}, title = {Scrape-Off-Layer Current Model for Filament Structure Observed during Edge-Localized Modes in the DIII-D Tokamak}, journal = {Physical Review Letters}, year = {2008}, volume = {100}, pages = {205001-4}, month = may, doi = {10.1103/PhysRevLett.100.205001}, keywords = {plasma instability,plasma magnetohydrodynamics,plasma oscillations,Tokamak devices}, url = {http://link.aps.org/abstract/PRL/v100/e205001} } @ARTICLE{tanaka_precise_2004, author = {K. Tanaka and A. L. Sanin and L. N. Vyacheslavov and T. Akiyama and K. Kawahata and T. Tokuzawa and Y. Ito and S. Okajima}, title = {Precise density profile measurements by using a two color {YAG/CO[sub} 2] laser imaging Interferometer on {LHD}}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, pages = {3429--3432}, number = {10}, month = oct, doi = {10.1063/1.1786643}, keywords = {light interferometers, plasma density, plasma diagnostics, plasma toroidal confinement, stellarators}, url = {http://link.aip.org/link/?RSI/75/3429/1} } @INPROCEEDINGS{tang_advanced_2002, author = {W. M. Tang}, title = {Advanced computations in plasma physics}, booktitle = {Review,Tutorial and Invited Papers from the 43rd Annual Meeting of the APS Division of Plasma Physics}, year = {2002}, volume = {9}, pages = {1856-1872}, address = {Long Beach, California (USA)}, month = may, publisher = {AIP}, doi = {10.1063/1.1467985}, journal = {Review,Tutorial and Invited Papers from the 43rd Annual Meeting of the APS Division of Plasma Physics}, keywords = {physics computing,plasma confinement,plasma magnetohydrodynamics,plasma simulation,plasma turbulence}, url = {http://link.aip.org/link/?PHP/9/1856/1} } @ARTICLE{tang_microinstabilities_1986, author = {W. M. Tang and G. Rewoldt and Liu Chen}, title = {Microinstabilities in weak density gradient tokamak systems}, journal = {Physics of Fluids}, year = {1986}, volume = {29}, pages = {3715--3718}, number = {11}, month = nov, doi = {10.1063/1.866014}, keywords = {{ELECTRIC} {DISCHARGES,} {PLASMA} {CONFINEMENT,} {PLASMA} {DENSITY,} {PLASMA} {HEATING,} {PLASMA} {MICROINSTABILITIES,} {TOKAMAK} {DEVICES}}, url = {http://link.aip.org/link/?PFL/29/3715/1} } @ARTICLE{taylor_enhanced_2003, author = {G. Taylor and P. C. Efthimion and B. Jones and B. P. {LeBlanc} and J. R. Wilson and J. B. Wilgen and G. L. Bell and T. S. Bigelow and R. Maingi and D. A. Rasmussen and R. W. Harvey and A. P. Smirnov and F. Paoletti and S. A. Sabbagh}, title = {Enhanced conversion of thermal electron Bernstein waves to the extraordinary electromagnetic mode on the National Spherical Torus Experiment}, journal = {Physics of Plasmas}, year = {2003}, volume = {10}, pages = {1395--1401}, number = {5}, month = may, doi = {10.1063/1.1564081}, keywords = {plasma Bernstein waves,plasma boundary layers,plasma instability,plasma toroidal confinement}, url = {http://link.aip.org/link/?PHP/10/1395/1} } @ARTICLE{taylor_efficient_2005, author = {G. Taylor and P. C. Efthimion and B. P. {LeBlanc} and M. D. Carter and J. B. Caughman and J. B. Wilgen and J. Preinhaelter and R. W. Harvey and S. A. Sabbagh}, title = {Efficient coupling of thermal electron Bernstein waves to the ordinary electromagnetic mode on the National Spherical Torus Experiment}, journal = {Physics of Plasmas}, year = {2005}, volume = {12}, pages = {052511--7}, number = {5}, month = may, doi = {10.1063/1.1891065}, keywords = {plasma beam injection heating,plasma Bernstein waves,plasma toroidal confinement,plasma transport processes}, url = {http://link.aip.org/link/?PHP/12/052511/1} } @ARTICLE{terry2000review, author = {Terry, P. W.}, title = {Suppression of turbulence and transport by sheared flow}, journal = {Rev. Mod. Phys.}, year = {2000}, volume = {72}, pages = {109--165}, number = {1}, month = {Jan}, doi = {10.1103/RevModPhys.72.109}, notes = {to read}, numpages = {56}, publisher = {American Physical Society} } @INPROCEEDINGS{thomas_direct_2002, author = {Jr. Thomas and Tracy M. Bahm and Larry R. Baylor and Philip R. Bingham and Steven W. Burns and Matt Chidley and Long Dai and Robert J. Delahanty and Christopher J. Doti and Ayman {El-Khashab} and Robert L. Fisher and Judd M. Gilbert and Jr. Goddard and Gregory R. Hanson and Joel D. Hickson and Martin A. Hunt and Kathy W. Hylton and George C. John and Michael L. Jones and Ken R. Macdonald and Michael W. Mayo and Ian {McMackin} and Dave R. Patek and John H. Price and David A. Rasmussen and Louis J. Schaefer and Thomas R. Scheidt and Mark A. Schulze and Philip D. Schumaker and Bichuan Shen and Randall G. Smith and Allen N. Su and Jr. Tobin and William R. Usry and Edgar Voelkl and Karsten S. Weber and Paul G. Jones and Robert W. Owen and Alexander Starikov and Kenneth W. Tobin and Jr.}, title = {Direct to digital holography for semiconductor wafer defect detection and review}, booktitle = {Design, Process Integration, and Characterization for Microelectronics}, year = {2002}, volume = {4692}, pages = {180--194}, address = {Santa Clara, {CA,} {USA}}, month = jul, publisher = {{SPIE}}, url = {http://link.aip.org/link/?PSI/4692/180/1} } @ARTICLE{thumm_high-power_1989, author = {Manfred Thumm and Helga Kumric}, title = {High-power {TE11} and {TM11} circular polarizers in oversized waveguides at 70 {GHz}}, journal = {International Journal of Infrared and Millimeter Waves}, year = {1989}, volume = {10}, pages = {1059--1075}, number = {9}, note = {{RF} waveguides, wave polarization}, abstract = {Elliptical deformation of oversized, smooth-wall circular waveguides can produce choosable elliptical or circular polarization from a linearly polarized {TE11} or {TM11} mode used as intermediate linearly polarized modes in {TEO1} to {HE11} mode conversion sequences in electron cyclotron resonance heating {(ECRH)} of magnetically confined thermonuclear fusion plasmas with high-power gyrotrons. Mode coupling in elliptically distorted overmoded circular waveguides has been studied theoretically and experimentally in order to optimize {TE11} (and {TM11)} polarizers {(I.D.=27.79} mm) for the 1 {MW/70} {GHz} long-pulse (3s) {ECRH} system on the Garching Stellarator W {VII-AS.} Coupling coefficients for ellipticity coupling of non-degenerate modes are given (coupled-mode differential equations formalism). The polarization converters essentially consist of smooth-wall circular waveguides which are gradually squeezed. A sine-squared function of the length coordinate is used to get an almost elliptical crosssection in the middle and circular cross sections at both ends. Arbitrary elliptical polarization states can be generated introducing an extremely low level ({\textless}{\textless}1\%) of undesired spurious modes. Well defined differential phase characteristics have been achieved.}, doi = {{10.1007/BF01010365}}, url = {http://dx.doi.org/10.1007/BF01010365} } @INPROCEEDINGS{tilley_coupling_1999, author = {Tilley, D.~L. and de Grys, K.~H. and Myers, R.~M.}, title = {Hall Thruster - Cathode Coupling}, booktitle = {35th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit}, year = {1999}, series = {AIAA paper 99-2865}, address = {Los Angeles, CA}, month = {JUN}, note = {finds optimal position of hollow cathode neutralizer; also looks at floating potential of cathode}, keywords = {1yr_project, hall thruster, hollow cathode}, owner = {erikg}, timestamp = {2008.03.28}, url = {http://www.aiaa.org/content.cfm?pageid=413} } @ARTICLE{told_gyrokinetic_2008, author = {D. Told and F. Jenko and P. Xanthopoulos and L. D. Horton and E. Wolfrum and {ASDEX} Upgrade Team}, title = {Gyrokinetic microinstabilities in {ASDEX} Upgrade edge plasmas}, journal = {Physics of Plasmas}, year = {2008}, volume = {15}, pages = {102306--11}, number = {10}, month = oct, doi = {10.1063/1.3000132}, keywords = {plasma boundary layers,plasma density,plasma flow,plasma kinetic theory,plasma simulation,plasma temperature,tearing {instability,Tokamak} devices}, url = {http://link.aip.org/link/?PHP/15/102306/1} } @ARTICLE{tomassini_generalization_2001, author = {P. Tomassini and A. Giulietti}, title = {A generalization of Abel inversion to non-axisymmetric density distribution}, journal = {Optics Communications}, year = {2001}, volume = {199}, pages = {143--148}, number = {1-4}, month = nov, doi = {{10.1016/S0030-4018(01)01575-9}}, issn = {0030-4018}, keywords = {Interferometry, Plasma diagnostics}, url = {http://www.sciencedirect.com/science/article/B6TVF-44762D1-4/2/46113089e1d44d686a5d469cdb29e095} } @ARTICLE{truc:3716, author = {A. Truc and A. Qu\'{e}m\'{e}neur and P. Hennequin and D. Gr\'{e}sillon and F. Gervais and C. Laviron and J. Olivain and S. K. Saha and P. Devynck}, title = {ALTAIR: An infrared laser scattering diagnostic on the TORE SUPRA tokamak}, journal = {Review of Scientific Instruments}, year = {1992}, volume = {63}, pages = {3716-3724}, number = {7}, abstract = {A collective laser light scattering diagnostic ALTAIR (a french acronym for local analysis of anomalous transport using infrared light), using a $CO_2$ laser beam ($\lambda=10.6 \mum$) has been realized to measure plasma density fluctuations in the TORE SUPRA tokamak. This article describes in detail the optical setup, the signal processing, acquisition, and control systems required for this experiment. As the density fluctuations propagating in tokamaks have small wave numbers and require small scattering angles, such scattering experiments are considered as having no resolution along the beam. However, taking advantage of the pitch angle variation of the magnetic field lines around the magnetic axis along a vertical chord, it has been possible to obtain partial spatial localization of the scattering volume by rotating the direction of the analyzed wave vector in a horizontal plane. Heterodyne detection is used to determine the fluctuations propagation direction. The experiment has been tested on acoustic waves and the first results obtained on TORE SUPRA indeed show the existence of a spatial resolution.}, doi = {10.1063/1.1143603}, keywords = {TORE SUPRA TOKAMAK; PLASMA DIAGNOSTICS; collective LIGHT SCATTERING; INFRARED RADIATION; PLASMA DENSITY; turbulence}, publisher = {AIP}, url = {http://link.aip.org/link/?RSI/63/3716/1} } @ARTICLE{tsai_theory_1993, author = {{Shih-Tung} Tsai and Liu Chen}, title = {Theory of kinetic ballooning modes excited by energetic particles in tokamaks}, journal = {Physics of Fluids B: Plasma Physics}, year = {1993}, volume = {5}, pages = {3284--3290}, number = {9}, doi = {10.1063/1.860624}, keywords = {{ALPHA} {PARTICLES,BALLOONING} {INSTABILITY,DISPERSION} {RELATIONS,DISTRIBUTION} {FUNCTIONS,INSTABILITY} {GROWTH} {RATES,IONS,MAGNETOHYDRODYNAMICS,TOKAMAK} {DEVICES}}, url = {http://link.aip.org/link/?PFB/5/3284/1} } @ARTICLE{1998PhRvE..57.5937T, author = {{Turlapov}, A.~V. and {Semenov}, V.~E.}, title = {{Confinement of a mirror plasma with an anisotropic electron distribution function}}, journal = {Phys. Rev. E}, year = {1998}, volume = {57}, pages = {5937-5944}, number = {5}, month = {May}, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/abs/1998PhRvE..57.5937T}, doi = {10.1103/PhysRevE.57.5937}, keywords = {mirror, open system, 2yr_project} } @ARTICLE{umansky_suite_2008, author = {M. V. Umansky and R. H. Cohen and L. L. {LoDestro} and X. Q. Xu}, title = {Suite of Verification Test Problems for Edge Turbulence Simulations}, journal = {Contributions to Plasma Physics}, year = {2008}, volume = {48}, pages = {27--31}, number = {1-3}, abstract = {We present a suite of test problems that are used for verification of the edge turbulence code {BOUT.} {BOUT} is an electromagnetic fluid turbulence code for tokamak edge plasma that performs time integration of reduced Braginskii plasma fluid equations, using spatial discretization in realistic geometry and employing a standard {ODE} integration package {PVODE.} Recently the code underwent a substantial redesign and extensive verification testing. In the verification process, a series of linear and nonlinear test problems was applied to {BOUT} targeting different subgroups of physical terms. The tests include reproducing basic electrostatic and electromagnetic plasma modes in simplified geometry, axisymmetric benchmarks against the {2D} edge code {UEDGE} in the actual {DIII-D} tokamak divertor geometry. Successful passing of these tests by {BOUT} gives strong evidence that equations in the code are solved correctly. Although the tests were developed specifically for the {BOUT} code they can well be applied for verification of other codes used for simulations of edge turbulence. (� 2008 {WILEY-VCH} Verlag {GmbH} \& Co. {KGaA,} Weinheim)}, doi = {10.1002/ctpp.200810004}, url = {http://dx.doi.org/10.1002/ctpp.200810004} } @ARTICLE{valeo_2D_reflectometry_2002, author = {E. J. Valeo and G. J. Kramer and R. Nazikian}, title = {Two-dimensional simulations of correlation reflectometry in fusion plasmas}, journal = {Plasma Physics and Controlled Fusion}, year = {2002}, volume = {44}, pages = {L1-L10}, abstract = {A two-dimensional wave propagation code, developed specifically to simulate correlation reflectometry in large-scale fusion plasmas, is described. The code makes use of separate computational methods in the vacuum, underdense and reflection regions of the plasma in order to obtain the high computational efficiency necessary for correlation analysis. Simulations of TFTR plasma with internal transport barriers are presented and compared with one-dimensional full-wave simulations. It is shown that the two-dimensional simulations are remarkably similar to the results of the one-dimensional full-wave analysis for a wide range of turbulent correlation lengths. Implications for the interpretation of correlation reflectometer measurements in fusion plasma are discussed.}, doi = {10.1088/0741-3335/44/2/101}, issn = {0741-3335} } @PHDTHESIS{volpe_electron_2003, author = {Volpe, Francesco A.G.}, title = {Electron Bernstein emission diagnostic of electron temperature profile at W7-AS Stellarator}, school = {University of Greifswald}, year = {2003}, month = {MAR}, abstract = {Electron temperature profiles at densities above the ECE cutoff are measured at the W7-AS stellarator by a novel diagnostic based on black body emission and mode conversion of electron Bernstein waves (EBWs). The EBWs, otherwise confined within the upper hybrid layers, reach the out- side of the plasma after Bernstein-extraordinary(X)-ordinary(O) mode conver- sion. Such O-mode polarised output is detected along a special oblique line of sight by an antenna with gaussian optic. This has been optimised by means of EBWs ray tracing calculations in full stellarator geometry, in order to maximise the conversion efficiency and to minimise the Doppler broadening due to the oblique nature of the line of sight. The obliquely detected O-mode polarization is elliptical, but by $\lambda/4$ phase shift and proper orientation of optical axes it is changed into a linear polarization by an elliptical waveguide. The signal is then spectrum-analysed in a heterodyne radiometer. Finally temperature profiles are derived from the spectra by means of the 3D ray tracing code mentioned before. The diagnostic has been applied to time- and space-resolved measurements of edge-localized modes, low-to-high confinement transitions and radiative collapses at densities up to ne = 3.8x10^20 m-3 . Moreover, for the first time the heat wave propagation method for the determi- nation of local heat transport coefficients has been extended beyond ECE cutoff density, combining EBW emission measurements at the first harmonic (f =66- 78GHz) with modulated EBW heating at the second harmonic (140GHz).}, file = {volpe_electron_2003.pdf:refs/theses/volpe_electron_2003.pdf:PDF}, keywords = {electron Bernstein wave, EBW, stellatators, ray tracing, emission, electron temperature}, owner = {erikg}, timestamp = {2009.06.01}, url = {http://www.engr.wisc.edu/ep/faculty/volpe_francesco.html} } @ARTICLE{volpe_bxo_2003, author = {F. Volpe and H. P. Laqua and the W7-AS Team}, title = {BXO mode-converted electron Bernstein emission diagnostic (invited)}, journal = {Papers from the 14th Topical Conference on High Temperature Plasma Diagnostics}, year = {2003}, volume = {74}, pages = {1409--1413}, month = mar, doi = {10.1063/1.1530379}, keywords = {blackbody radiation,electromagnetic wave polarisation,plasma Bernstein waves,plasma diagnostics,plasma radiofrequency heating,plasma temperature,radiometry,ray tracing,spectral analysis,stellarators}, url = {http://link.aip.org/link/?RSI/74/1409/1} } @INPROCEEDINGS{vyacheslavov_new_capabilities_interferometry_2002, author = {L.N.~Vyacheslavov and K.~Tanaka and T.~Akiyama and K.~Kawahata and S.~Okajima and A.L.~Sanin and S.~Iio}, title = {Search for New Capabilities of Imaging Interferometry on LHD}, booktitle = {29th EPS Conference on Plasma Physics and Controlled Fusion}, year = {2002}, volume = {26B}, pages = {P5.105}, address = {Montreux}, month = {JUN}, publisher = {European Physical Society}, file = {vyacheslavov_new_capabilities_interferometry_2002.pdf:refs/papers/vyacheslavov_new_capabilities_interferometry_2002.pdf:PDF}, keywords = {LHD, interferometer, PCI, phase contrast imaging}, owner = {erikg}, timestamp = {2009.07.22}, url = {http://epsppd.epfl.ch/Montreux/html/contents.htm} } @ARTICLE{vyacheslavov_application_2006, author = {L. N. Vyacheslavov and A. D. Khilchenko and P. V. Zubarev and K. Tanaka and C. Michael and A. L. Sanin and K. Kawahata and S. Okajima}, title = {Application of precise phase detector for density profile and fluctuation measurements using {CO2} imaging heterodyne interferometer on {LHD}}, journal = {Rev. Sci. Instrum.}, year = {2006}, volume = {77}, pages = {10E909--3}, month = oct, doi = {10.1063/1.2229273}, keywords = {light interferometry,phase detectors,plasma density,plasma diagnostics,plasma fluctuations,plasma toroidal confinement,stellarators}, url = {http://link.aip.org/link/?RSI/77/10E909/1} } @ARTICLE{vyacheslavov_2-d_2005, author = {{L.N.} Vyacheslavov and K. Tanaka and {A.L.} Sanin and K. Kawahata and C. Michael and T. Akiyama}, title = {2-D phase contrast imaging of turbulence structure on LHD}, journal = {Plasma Science, IEEE Transactions on}, year = {2005}, volume = {33}, pages = {464--465}, number = {2}, abstract = {{CO2} laser-based phase contrast imaging {(PCI)} equipped with a 6 by 8 element two-dimensional {(2-D)} array of photoconductors is used on the large helical device {(LHD)} for studying plasma density microfluctuations. Observing {2-D} structures of turbulence and strong magnetic shear along the viewing line on {LHD} permit conversion of a {2-D-PCI} image to a {2-D} picture of the radial distribution of the turbulence k-spectrum. The {PCI} images are sampled at 1 {MHz} so the images or associated spectral distributions, when assembled in a movie, present the dynamic radial structure of turbulence.}, doi = {{10.1109/TPS.2005.845955}}, issn = {0093-3813}, keywords = {1 {MHz,2D} {PCI} {image,2D} phase contrast {imaging,Anomalous} {transport,CO2} laser-based phase contrast imaging,fusion plasma,large helical {device,LHD,magnetic} confinement,microturbulence,phase contrast,plasma density,plasma density microfluctuations,plasma diagnostics,plasma fluctuations,plasma toroidal confinement,plasma turbulence,stellarators,strong magnetic shear,turbulence k-spectrum radial distribution,turbulence structure,two-dimensional photoconductor array} } @ARTICLE{wagner_regime_1982, author = {F. Wagner and G. Becker and K. Behringer and D. Campbell and A. Eberhagen and W. Engelhardt and G. Fussmann and O. Gehre and J. Gernhardt and G. v. Gierke and G. Haas and M. Huang and F. Karger and M. Keilhacker and O. Kl{\textbackslash}"uber and M. Kornherr and K. Lackner and G. Lisitano and G. G. Lister and H. M. Mayer and D. Meisel and E. R. M{\textbackslash}"uller and H. Murmann and H. Niedermeyer and W. Poschenrieder and H. Rapp and H. R{\textbackslash}"ohr}, title = {Regime of Improved Confinement and High Beta in {Neutral-Beam-Heated} Divertor Discharges of the {ASDEX} Tokamak}, journal = {Physical Review Letters}, year = {1982}, volume = {49}, pages = {1408}, number = {19}, month = nov, note = {H-mode, L-mode}, abstract = {A new operational regime has been observed in neutral-injection-heated {ASDEX} divertor discharges. This regime is characterized by high βp values comparable to the aspect ratio A {(βp{\textless}{\textasciitilde}0.65A)} and by confinement times close to those of Ohmic discharges. The high-βp regime develops at an injection power ≥1.9 {MW,} a mean density n̅ e{\textgreater}{\textasciitilde}3×1013 cm-3, and a q(a) value ≥2.6. Beyond these limits or in discharges with material limiter, low βp values and reduced particle and energy confinement times are obtained compared to the Ohmic heating phase.}, doi = {{10.1103/PhysRevLett.49.1408}}, url = {http://link.aps.org/abstract/PRL/v49/p1408} } @ARTICLE{walker_backpressure_2005, author = {Walker, M.~L.~R. and A. Victor and R.~Hofer and A. Gallimore}, title = {Effect of Backpressure on Ion Current Density Measurements in Hall Thruster Plumes}, journal = {Journal of Propulsion and Power}, year = {2005}, volume = {21}, pages = {408--415}, number = {3}, note = {AIAA paper no. 0748-4658}, keywords = {1yr\_project, backpressure, background pressure, charge exchange, Hall thruster}, owner = {erikg}, timestamp = {2008.04.01}, url = {http://www.aiaa.org/content.cfm?pageid=318} } @ARTICLE{waltz_toroidal_1994, author = {R. E. Waltz and G. D. Kerbel and J. Milovich}, title = {Toroidal {gyro-Landau} fluid model turbulence simulations in a nonlinear ballooning mode representation with radial modes}, journal = {Physics of Plasmas}, year = {1994}, volume = {1}, pages = {2229--2244}, number = {7}, month = jul, doi = {10.1063/1.870934}, keywords = {{BALLOONING} {INSTABILITY,FLUID} {MODELS,FOURIER} {ANALYSIS,HELICITY,ION} {TEMPERATURE,KINETIC} {EQUATIONS,PLASMA} {DRIFT,PLASMA} {SIMULATION,TOKAMAK} {DEVICES,TRANSPORT} {THEORY,TURBULENCE}}, url = {http://link.aip.org/link/?PHP/1/2229/1} } @ARTICLE{waltz_ion_1999, author = {R. E. Waltz and R. L. Miller}, title = {Ion temperature gradient turbulence simulations and plasma flux surface shape}, journal = {Physics of Plasmas}, year = {1999}, volume = {6}, pages = {4265-4271}, month = nov, note = {From Greg Hammett: table 1 actually uses a shift of -0.354 not -0.345 as written in the text.}, doi = {10.1063/1.873694}, keywords = {BALLOONING INSTABILITY,ION TEMPERATURE,MAGNETIC FIELDS,MHD EQUILIBRIUM,plasma magnetohydrodynamics,PLASMA SIMULATION,plasma temperature,plasma turbulence,SHEAR,TEMPERATURE GRADIENTS,TURBULENCE}, url = {http://link.aip.org/link/?PHP/6/4265/1} } @ARTICLE{waltz_gyro-landau-fluid_1997, author = {R. E. Waltz and G. M. Staebler and W. Dorland and G. W. Hammett and M. Kotschenreuther and J. A. Konings}, title = {A gyro-Landau-fluid transport model}, journal = {Physics of Plasmas}, year = {1997}, volume = {4}, pages = {2482--2496}, number = {7}, month = jul, doi = {10.1063/1.872228}, keywords = {BALLOONING INSTABILITY, CHARGED-PARTICLE TRANSPORT THEORY, plasma instability, plasma simulation, plasma toroidal confinement, plasma transport processes, plasma turbulence, STABILIZATION}, url = {http://link.aip.org/link/?PHP/4/2482/1} } @ARTICLE{wang_monte_1996, author = {W.X. Wang and M. Okamoto and N. Nakajima and S. Murakami and N. Ohyabu}, title = {A Monte Carlo model for velocity space effects in low recycling scrape-off layer plasmas}, journal = {Nuclear Fusion}, year = {1996}, volume = {36}, pages = {1633-1646}, abstract = {A Monte Carlo model solving only in velocity space is proposed to investigate a low recycling scrape-off layer (SOL) plasma. In the model, the effects of Coulomb collisions are accurately described by a non-linear Monte Carlo collision operator; a conductive heat flux into the SOL is effectively modelled via randomly exchanging the source particles and the SOL particles; secondary electrons are included. A steady state SOL plasma, which satisfies the particle and energy balances and the neutrality constraint, is determined in terms of the total particle and heat fluxes across the separatrix, the edge plasma temperature, the secondary electron emission coefficient and the SOL size. The model gives gross features of the SOL, such as plasma temperatures and densities, the total sheath potential drop and the sheath energy transmission factor. Simulations neglecting unlike collisions are performed. It is found that the potential drop and the electron energy transmission factor in collisional SOL plasmas are in close agreement with theoretical predictions. The present model primarily provides useful information about collisionless SOL plasmas that is difficult to obtain analytically}, doi = {10.1088/0029-5515/36/12/I04}, issn = {0029-5515}, keywords = {scrape-off layer,sheath,SOL}, url = {http://www.iop.org/EJ/abstract/0029-5515/36/12/I04/} } @ARTICLE{wang_gyro-kinetic_2006, author = {W. X. Wang and Z. Lin and W. M. Tang and W. W. Lee and S. Ethier and J. L. V. Lewandowski and G. Rewoldt and T. S. Hahm and J. Manickam}, title = {Gyro-kinetic simulation of global turbulent transport properties in tokamak experiments}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {092505-12}, keywords = {plasma collision processes,plasma flow,plasma nonlinear processes,plasma oscillations,plasma simulation,plasma toroidal confinement,plasma transport processes,plasma turbulence,Tokamak devices}, url = {http://link.aip.org/link/?PHP/13/092505/1} } @ARTICLE{wang_nonlocal_2006, author = {W. X. Wang and G. Rewoldt and W. M. Tang and F. L. Hinton and J. Manickam and L. E. Zakharov and R. B. White and S. Kaye}, title = {Nonlocal neoclassical transport in tokamak and spherical torus experiments}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {082501-15}, url = {http://link.aip.org/link/?PHP/13/082501/1} } @ARTICLE{wang_global_2004, author = {W. X. Wang and W. M. Tang and F. L. Hinton and L. E. Zakharov and R. B. White and J. Manickam}, title = {Global [delta]f particle simulation of neoclassical transport and ambipolar electric field in general geometry}, journal = {Computer Physics Communications}, year = {2004}, volume = {164}, pages = {178-182}, month = dec, abstract = {A generalized global particle-in-cell (PIC) code has been developed to systematically study neoclassical physics and equilibrium electric field dynamics in general toroidal geometry. This capability enables realistic assessment of the irreducible minimum transport level and the bootstrap current in toroidal systems. The associated analysis takes into account the comprehensive influences of large orbits, toroidal geometry, and self-consistent electric field, for more meaningful experimental comparisons. The simulation model and [delta]f algorithm are described, and an interesting new result of non-local ion thermal transport is presented.}, doi = {10.1016/j.cpc.2004.06.027}, url = {http://www.sciencedirect.com/science/article/B6TJ5-4CX71G2-1/2/c2de248a98052c1cb241dc4a821006d2} } @ARTICLE{ware70, author = {A. Ware}, journal = {Physics Review Letters}, year = {1970}, volume = {25}, pages = {15}, keywords = {GPP2, trapped particles, ware pinch, tokamak, neoclassical}, owner = {Administrator}, timestamp = {2007.04.07} } @ARTICLE{weisen_phase_1988, author = {H. Weisen}, title = {The phase contrast method as an imaging diagnostic for plasma density fluctuations (invited)}, journal = {Review of Scientific Instruments}, year = {1988}, volume = {59}, pages = {1544-1549}, doi = {10.1063/1.1140193 }, keywords = {IMAGES,INFRARED RADIATION,LIGHT SCATTERING,LIGHT TRANSMISSION,PCI,phase contrast imaging,PHASE SHIFT,PLASMA DENSITY,PLASMA DIAGNOSTICS,TCA TOKAMAK}, url = {http://link.aip.org/link/?RSI/59/1544/1} } @BOOK{wesson_tokamaks_2004, title = {Tokamaks}, publisher = {Clarendon Press}, year = {2004}, author = {John Wesson and D. J Campbell}, pages = {749}, address = {Oxford}, edition = {3rd ed}, isbn = {0198509227}, keywords = {Tokamaks} } @ARTICLE{wheeler_supernovae_2006, author = {J. Craig Wheeler}, title = {Supernovae and gamma-ray bursts: Relativistic plasma physics in the Einstein centennial}, journal = {Physics of Plasmas}, year = {2006}, volume = {13}, pages = {058101}, file = {\\Docs\\general papers\\wheeler_supernovae_2006.pdf:\\Docs\\general papers\\wheeler_supernovae_2006.pdf:PDF}, keywords = {astrophysics}, url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal\&id=PHPAEN000013000005058101000001\&idtype=cvips\&gifs=Yes} } @ARTICLE{white_measurements_2008, author = {A. E. White and L. Schmitz and G. R. McKee and C. Holland and W. A. Peebles and T. A. Carter and M. W. Shafer and M. E. Austin and K. H. Burrell and J. Candy and J. C. DeBoo and E. J. Doyle and M. A. Makowski and R. Prater and T. L. Rhodes and G. M. Staebler and G. R. Tynan and R. E. Waltz and G. Wang}, title = {Measurements of core electron temperature and density fluctuations in DIII-D and comparison to nonlinear gyrokinetic simulations}, journal = {Physics of Plasmas}, year = {2008}, volume = {15}, pages = {056116-11}, month = may, doi = {10.1063/1.2895408}, keywords = {electron density,plasma heating,plasma transport processes,Tokamak devices}, url = {http://link.aip.org/link/?PHP/15/056116/1} } @ARTICLE{white_correlation_2008, author = {A. E. White and L. Schmitz and W. A. Peebles and T. A. Carter and T. L. Rhodes and E. J. Doyle and P. A. Gourdain and J. C. Hillesheim and G. Wang and C. Holland and G. R. Tynan and M. E. Austin and G. R. {McKee} and M. W. Shafer and K. H. Burrell and J. Candy and J. C. {DeBoo} and R. Prater and G. M. Staebler and R. E. Waltz and M. A. Makowski}, title = {A correlation electron cyclotron emission diagnostic and the importance of multifield fluctuation measurements for testing nonlinear gyrokinetic turbulence simulations}, journal = {Review of Scientific Instruments}, year = {2008}, volume = {79}, pages = {103505}, number = {10}, doi = {10.1063/1.2981186}, issn = {00346748}, url = {http://link.aip.org/link/RSINAK/v79/i10/p103505/s1&Agg=doi} } @BOOK{whitetoroidallyconfined, title = {Theory of Toroidally Confined Plasmas}, publisher = {Imperial College Press}, year = {2001}, author = {R. B. White}, note = {Princeton Library Catalog: http://lsapps1.princeton.edu/cgi-bin/Pwebrecon.cgi?v1=2\&ti=1,2\&Search_Arg=theory%20of%20toroidally%20confined%20plasmas\&Search_Code=TALL\&CNT=50\&PID=k8ZL1xrV06K4C538oC-FpkSeJAz\&SEQ=20080715142701\&SID=1 page 42: $B^\theta = 1/(qJ)$, $q=d\psi/d\psi_p$}, keywords = {GPP2, tokamak}, owner = {Administrator}, timestamp = {2007.04.07}, url = {http://books.google.com/books?id=AhsphOnXQm8C&printsec=frontcover&sig=ACfU3U1nJyvBmUPDN_bnUa6f-19Mv_8njw&source=gbs_ViewAPI#PPP1,M1} } @ARTICLE{wilmshurst_vibrational_1962, author = {J. K. Wilmshurst}, title = {Vibrational Spectra of Inorganic Molecules. {IV.} Infrared Reflection Spectra of Liquid Lithium, Sodium, Potassium and Silver Chlorates, and Liquid Lithium Perchlorate}, journal = {The Journal of Chemical Physics}, year = {1962}, volume = {36}, pages = {2415--2419}, number = {9}, month = may, doi = {10.1063/1.1732900}, url = {http://link.aip.org/link/?JCP/36/2415/1} } @ARTICLE{winglee2007, author = {R. Winglee and T. Ziemba and L. Giersch and J. Prager and J. Carscadden and B. R. Roberson}, title = {Simulation and laboratory validation of magnetic nozzle effects for the high power helicon thruster}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {063501}, number = {6}, eid = {063501}, abstract = {The efficiency of a plasma thruster can be improved if the plasma stream can be highly focused, so that there is maximum conversion of thermal energy to the directed energy. Such focusing can be potentially achieved through the use of magnetic nozzles, but this introduces the potential problem of detachment of plasma from the magnetic field lines tied to the nozzles. Simulations and laboratory testing are used to investigate these processes for the high power helicon (HPH) thruster, which has the capacity of producing a dense (1018?1020 m?3) energetic (tens of eV) plasma stream which can be both supersonic and super-Alfvnic within a few antenna wavelengths. In its standard configuration, the plasma plume generated by this device has a large opening angle, due to relatively high thermal velocity and rapid divergence of the magnetic field. With the addition of a magnetic nozzle system, the plasma can be directed/collimated close to the pole of the nozzle system causing an increase in the axial velocity of the plasma, as well as an increase in the Alfvn Mach number. As such the magnetic field of the nozzle is insufficient to pull the plasma back to the spacecraft, i.e., plasma attachment is not a problem for the system. Laboratory results show that the specific impulse (Isp) of the system can be increased by ~30% by the addition of the nozzle due to the conversion of thermal energy into directed energy in association with a highly collimated profile. An interesting feature of the system is that self-collimation of the beam is expected to occur during continuous operation through plasma currents induced downstream from the magnetic nozzle. These currents lead to magnetic fields that have a smaller divergence than the original vacuum magnetic field so that the following plasma will be more collimated than the proceeding plasma. This self-focusing can lead to beam propagation over extended distances.}, doi = {10.1063/1.2734184}, keywords = {thrusters, plasma transport processes; Mach number; plasma Alfven waves; propulsion, 1yr_project}, numpages = {14}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/14/063501/1} } @ARTICLE{wright83, author = {{Wright}, Jr., K.~H. and {Stone}, N.~H. and {Samir}, U.}, title = {{The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics}}, journal = {Reviews of Geophysics and Space Physics}, year = {1983}, volume = {21}, pages = {1631-1646}, month = aug, adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System}, adsurl = {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1983RvGSP..21.1631W&db_key=PHY}, keywords = {plasma expansion, 1yr_project} } @ARTICLE{wukitch_double_2002, author = {S. J. Wukitch and R. L. Boivin and P. T. Bonoli and C. L. Fiore and R. S. Granetz and M. J. Greenwald and A. E. Hubbard and I. H. Hutchinson and Y. In and J. Irby and Y. Lin and E. S. Marmar and D. Mossessian and M. Porkolab and G. Schilling and J. E. Rice and J. A. Snipes and S. M. Wolfe Alcator C-Mod group}, title = {Double transport barrier experiments on Alcator {C-Mod}}, journal = {Physics of Plasmas}, year = {2002}, volume = {9}, pages = {2149--2155}, month = may, doi = {10.1063/1.1467347}, keywords = {plasma impurities,plasma radiofrequency heating,plasma toroidal confinement,plasma transport processes,sawtooth instability,thermal diffusivity, ICRH, ITB, internal transport barrier}, url = {http://link.aip.org/link/?PHP/9/2149/1} } @ARTICLE{xiong_high-order_2008, author = {Z. Xiong and {R.H.} Cohen and {T.D.} Rognlien and {X.Q.} Xu}, title = {A high-order finite-volume algorithm for {Fokker-Planck} collisions in magnetized plasmas}, journal = {Journal of Computational Physics}, year = {2008}, volume = {227}, pages = {7192--7205}, number = {15}, month = jul, abstract = {A high-order finite-volume algorithm is developed for the {Fokker-Planck} Operator {(FPO)} describing Coulomb collisions in strongly magnetized plasmas. The algorithm uses a generic fourth-order reconstruction scheme on an unstructured grid in the velocity space spanned by parallel velocity and magnetic moment. By analytically mapping between different coordinates, it produces an accurate and density-conserving numerical {FPO} for an arbitrary choice of velocity space coordinates. A linearized {FPO} in constants-of-motion coordinates is implemented as an example of the present algorithm combined with a cut-cell merging procedure. Numerical tests include the thermalization of a test distribution with a background Maxwellian at a different temperature, and the return to isotropy for a distribution initialized with a velocity space loss-cone. Utilization of the method for a nonlinear {FPO} is straightforward but requires evaluation of the {Trubnikov-Rosenbluth} potentials.}, doi = {10.1016/j.jcp.2008.04.004}, issn = {0021-9991}, keywords = {Constants-of-motion coordinates, Finite volume, Fokker-Planck collisions, High-order scheme, Landau collision operator}, url = {http://www.sciencedirect.com/science/article/B6WHY-4S92TT6-5/2/965d9fb60d59b0499995f4dfd5ba8e16} } @ARTICLE{xu_edge_2007, author = {X.Q. Xu and Z. Xiong and M.R. Dorr and J.A. Hittinger and K. Bodi and J. Candy and B.I. Cohen and R.H. Cohen and P. Colella and G.D. Kerbel and S. Krasheninnikov and W.M. Nevins and H. Qin and T.D. Rognlien and P.B. Snyder and M.V. Umansky}, title = {Edge gyrokinetic theory and continuum simulations}, journal = {Nuclear Fusion}, year = {2007}, volume = {47}, pages = {809-816}, number = {8}, month = {AUG}, note = {google pastukhov cohen tempest gyrokinetic to find additional presentations}, abstract = {The following results are presented from the development and application of TEMPEST, a fully nonlinear (full-f) five-dimensional (3d2v) gyrokinetic continuum edge-plasma code. (1) As a test of the interaction of collisions and parallel streaming, TEMPEST is compared with published analytic and numerical results for endloss of particles confined by combined electrostatic and magnetic wells. Good agreement is found over a wide range of collisionality, confining potential and mirror ratio, and the required velocity space resolution is modest. (2) In a large-aspect-ratio circular geometry, excellent agreement is found for a neoclassical equilibrium with parallel ion flow in the banana regime with zero temperature gradient and radial electric field. (3) The four-dimensional (2d2v) version of the code produces the first self-consistent simulation results of collisionless damping of geodesic acoustic modes and zonal flow (Rosenbluth-Hinton residual) with Boltzmann electrons using a full-f code. The electric field is also found to agree with the standard neoclassical expression for steep density and ion temperature gradients in the plateau regime. In divertor geometry, it is found that the endloss of particles and energy induces parallel flow stronger than the core neoclassical predictions in the SOL.}, doi = {10.1088/0029-5515/47/8/011}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/47/8/011} } @ARTICLE{xu_neoclassical_2008, author = {X. Q. Xu}, title = {Neoclassical simulation of tokamak plasmas using the continuum gyrokinetic code {TEMPEST}}, journal = {Physical Review E {(Statistical,} Nonlinear, and Soft Matter Physics)}, year = {2008}, volume = {78}, pages = {016406--11}, number = {1}, month = jul, doi = {{10.1103/PhysRevE.78.016406}}, keywords = {Boltzmann equation,finite difference methods,plasma kinetic theory,plasma simulation,plasma toroidal confinement,plasma transport {processes,Poisson} {equation,Tokamak} devices}, url = {http://link.aps.org/abstract/PRE/v78/e016406} } @ARTICLE{yamabe1983, author = {Yamabe, C. and Buckman, S. J. and Phelps, A. V.}, title = {Measurement of free-free emission from low-energy-electron collisions with Ar}, journal = {Phys. Rev. A}, year = {1983}, volume = {27}, pages = {1345--1352}, number = {3}, month = {Mar}, doi = {10.1103/PhysRevA.27.1345}, keywords = {cross-section, Ar, Argon, 1yr_project}, numpages = {7}, publisher = {American Physical Society} } @ARTICLE{yamadareview2007, author = {Masaaki Yamada}, title = {Progress in understanding magnetic reconnection in laboratory and space astrophysical plasmas}, journal = {Physics of Plasmas}, year = {2007}, volume = {14}, pages = {058102}, number = {5}, eid = {058102}, doi = {10.1063/1.2740595}, keywords = {magnetic reconnection; plasma magnetohydrodynamics; plasma collision processes; astrophysical plasma; solar flares; reviews}, numpages = {16}, publisher = {AIP}, url = {http://link.aip.org/link/?PHP/14/058102/1} } @ARTICLE{yates_simultaneous_2008, author = {T. F. Yates and W. X. Ding and T. A. Carter and D. L. Brower}, title = {Simultaneous density and magnetic field fluctuation measurements by far-infrared interferometry and polarimetry in {MST}}, journal = {Review of Scientific Instruments}, year = {2008}, volume = {79}, pages = {{10E714}}, number = {10}, doi = {10.1063/1.2966377}, issn = {00346748}, url = {http://link.aip.org/link/RSINAK/v79/i10/p10E714/s1&Agg=doi} } @ARTICLE{yoshikawa1962, author = {Yoshikawa, S. and Ross, D.J.}, title = {Anomalous Diffusion across a Magnetic Field}, journal = {Physics of Fluids}, year = {1962}, volume = {5}, pages = {334-340}, number = {3}, month = mar, keywords = {nsf_app, anomalous diffusion, cross-field diffusion, 1yr_project}, owner = {egranste}, timestamp = {2007.05.10} } @ARTICLE{zakharov_ignited_2004, author = {LE Zakharov and NN Gorelenkov and RB White and SI Krasheninnikov and GV Pereverzev}, title = {Ignited spherical tokamaks and plasma regimes with LiWalls}, journal = {FUSION ENGINEERING AND DESIGN}, year = {2004}, volume = {72}, pages = {149-168}, month = nov, abstract = {Basic requirements of the fusion power reactor and its development are outlined. The notion of operational power reactor regime (OPRR) is introduced explicitly for the first time in order to distinguish it from the relatively short ignition phase of the reactor operation. Development of OPRR is intrinsically linked to two basic technology objectives, i.e., development of the first wall (FW) and the tritium cycle (TC). The paper reveals an existing fundamental gap in the reactor development path associated with the lack of necessary amounts of tritium for the reactor design development. In this regard, low recycling regimes with a plasma limited by a lithium wall surface suggest enhanced stability and energy confinement, both necessary for tokamak power reactors. These regimes also could make ignition and OPRR feasible in compact tokamaks. Ignited spherical tokamaks (IST), self-sufficient in the bootstrap current, are introduced as a necessary interim step for development OPRR-FW-TC for the power reactors. (C) 2004 Elsevier B.V. All rights reserved.}, doi = {10.1016/j.fusengdes.2004.07.015 }, issn = {0920-3796}, url = {http://apps.isiknowledge.com/full\_record.do?product=WOS\&search\_mode=GeneralSearch\&qid=1\&SID=Q2J@mggJ5CJ8Dd5OJFB\&page=1\&doc=2} } @ARTICLE{zarnstorff_parallel_1990, author = {M. C. Zarnstorff and K. {McGuire} and M. G. Bell and B. Grek and D. Johnson and D. {McCune} and H. Park and A. Ramsey and G. Taylor}, title = {Parallel electric resistivity in the {TFTR} tokamak}, journal = {Physics of Fluids B: Plasma Physics}, year = {1990}, volume = {2}, pages = {1852--1857}, number = {8}, doi = {10.1063/1.859456}, keywords = {{CORRELATIONS,ELECTRIC} {CONDUCTIVITY,JOULE} {HEATING,MAGNETIC} {SURFACES,MAGNETIZATION,MAGNETOHYDRODYNAMICS,PLASMA,TFTR} {TOKAMAK}}, url = {http://link.aip.org/link/?PFB/2/1852/1} } @ARTICLE{zhou_numerical_2001, author = {Zhou and Li and Shu}, title = {Numerical Comparison of WENO Finite Volume and Runge?Kutta Discontinuous Galerkin Methods}, journal = {Journal of Scientific Computing}, year = {2001}, volume = {16}, pages = {145-171}, month = jun, abstract = {High order WENO (weighted essentially non-oscillatory) schemes and discontinuous Galerkin methods are two classes of high order, high resolution methods suitable for convection dominated simulations with possible discontinuous or sharp gradient solutions. In this paper we first review these two classes of methods, pointing out their similarities and differences in algorithm formulation, theoretical properties, implementation issues, applicability, and relative advantages. We then present some quantitative comparisons of the third order finite volume WENO methods and discontinuous Galerkin methods for a series of test problems to assess their relative merits in accuracy and CPU timing.}, doi = {10.1023/A:1012282706985}, url = {http://dx.doi.org/10.1023/A:1012282706985} } @ARTICLE{zhu_observation_2006, author = {W. Zhu and S. A. Sabbagh and R. E. Bell and J. M. Bialek and M. G. Bell and B. P. LeBlanc and S. M. Kaye and F. M. Levinton and J. E. Menard and K. C. Shaing and A. C. Sontag and H. Yuh}, title = {Observation of Plasma Toroidal-Momentum Dissipation by Neoclassical Toroidal Viscosity}, journal = {Physical Review Letters}, year = {2006}, volume = {96}, pages = {225002-4}, month = jun, keywords = {neoclassical toroidal viscosity,NTV}, url = {http://link.aps.org/abstract/PRL/v96/e225002} } @ARTICLE{zhurovich_microturbulent_2007, author = {K. Zhurovich and C.L. Fiore and D.R. Ernst and P.T. Bonoli and M.J. Greenwald and A.E. Hubbard and J.W. Hughes and E.S. Marmar and D.R. Mikkelsen and P. Phillips and J.E. Rice}, title = {Microturbulent drift mode suppression as a trigger mechanism for internal transport barriers on Alcator C-Mod}, journal = {Nuclear Fusion}, year = {2007}, volume = {47}, pages = {1220-1231}, abstract = {Internal transport barriers (ITBs) can be routinely produced in enhanced Da (EDA) H-mode discharges on the Alcator C-Mod tokamak by putting the minority ion cyclotron resonance layer at |r/a| [?] 0.5 during the current flat top phase of the discharge. These ITBs are characterized by density peaking at constant temperature and are therefore both particle and energy transport barriers. The ITB formation appears to result from widening the region near the magnetic axis in which toroidal drift modes are stable, allowing the Ware pinch to peak the density profile. Experimental evidence shows that shifting the ICRF resonance off-axis results in a local flattening of ion and electron temperature profiles. TRANSP calculations of ion temperature profiles support this experimentally observed trend. Stability analysis of ion temperature gradient (ITG) and electron temperature gradient modes at times before ITB formation is done using the linear gyrokinetic code GS2. These gyrokinetic calculations find that the most unstable modes in the C-Mod EDA H-mode core, prior to ITB onset, are the toroidal ITG driven type. These modes are suppressed in the ITB region through a temperature gradient reduction when the ICRF resonance is shifted off-axis.}, issn = {0029-5515}, url = {http://www.iop.org/EJ/abstract/0029-5515/47/9/019/} } @BOOK{barker_high-power_2001, title = {High-power Microwave Sources and Technologies}, publisher = {IEEE Press}, year = {2001}, editor = {Robert J Barker and Edl Schamiloglu}, pages = {485}, series = {IEEE Press series on RF and microwave technology}, address = {New York}, note = {\\subsubsection\{6.2.1.1\} Output window is most critical element for determining pulse duration. Best is Chemical Vapor Deposition (CVD) diamond. (According to Majeski windows are often double-pane, flow gas through middle to cool; alternative = edge cooling only.) One way to increase efficiency is to increase the ratio of electron orbital (perpendicular) to axial velocities, since in the CMR, energy removed from perp. component of beam to field; hence parallel energy is a source of inefficiency. \\subsubsection\{6.4.1.1 Frequency-Multiplying Gyro-Amplifiers\} 3 cavity GKL: input operates at fundamental resonance, 2nd at either fund. or 2nd harmonic, and output operates at one of 1st 4 harmonics}, isbn = {0780360060}, keywords = {devices,Microwave} } @BOOK{granatstein_high-power_1987, title = {High-power Microwave Sources}, publisher = {Artech House}, year = {1987}, editor = {V. L Granatstein and Igor Alexeff}, pages = {564}, series = {The Artech House microwave library}, address = {Boston}, note = {"This volume grew out of the ... three-day minicourse entitled, 'Generation of high-power microwaves, millimeter waves, and submillimeter waves,' which was held in conjunction with the 1985 IEEE International Conference on Plasma Science [held in Pittsburgh, Pa.]"--Pref. p.107: to provide a strong interaction, guiding centers of e-beam must be in a location where the transverse E-field is strong; ex. for TE\_\{01\} mode, gives a hollow ring (annulus) pattern, which nicely matches the natural beam pattern of the electron MIG. Longitudinal velocity spread <\~ 20\% typical, for gyro-TWT or GKL need <5\% since the interaction is over a longer distance p. 107-110: CMR is a fast-wave interaction (\\omega/k>c) p.120-121: Harmonic interactions note that in eqn 4.9, if you take n=1, t=0,z=0 for simplicity, just get cos(\\phi)\\hat\{r\} + sin(\\phi)\\hat\{\\phi\}, which is \\hat\{x\}: ie a rotating field vector}, isbn = {0890062412}, keywords = {Microwave,Oscillators} } @MISC{_bayard-alpert_, title = {Bayard-Alpert Gauge Filaments: Tungsten or}, keywords = {filament}, publisher = {Stanford Research Systems, Inc.}, url = {http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/IG1filamentsapp.pdf} } @MISC{_thermionic_, title = {Thermionic Emission}, keywords = {thermionic emission,tungsten}, url = {http://www.public.asu.edu/\~gbadams/spr06/334/Thermionic.pdf} } @MISC{uiowaQmachine, title = {Q Machines: A brief Introduction}, howpublished = {Web}, keywords = {q machine}, owner = {egranste}, timestamp = {2007.10.03}, url = {http://www.physics.uiowa.edu/xplasma/Qmachine.html} } @MISC{_determination_1998, title = {Determination of particle transport coefficients in reversed shear plasma of {JT-60U} }, howpublished = {{https://libserv7.princeton.edu:82/pul/nph-pul2.cgi/000000A/http/www.iop.org/EJ/abstract/0741-3335/40/2/002}}, month = feb, year = {1998}, url = {https://libserv7.princeton.edu:82/pul/nph-pul2.cgi/000000A/http/www.iop.org/EJ/abstract/0741-3335/40/2/002} } @INBOOK{sheathheatSEE66, chapter = {Heat Flow through a Langmuir sheath in the presence of electron emission}, pages = {85---87}, title = {Plasma Physics}, publisher = {Pergamon Press}, year = {1967}, volume = {9}, address = {Northern Ireland}, keywords = {sheath, electron emission, 1yr project}, owner = {egranste}, timestamp = {2007.06.25} }