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Title: Testing Gyrokinetics on C-Mod and NSTX

Abstract

Quantitative benchmarks of computational physics codes against experiment are essential for the credible application of such codes. Fluctuation measurements can provide necessary critical tests of nonlinear gyrokinetic simulations, but such require extraordinary computational resources. Linear micro-stability calculations with the GS2 [1] gyrokinetic code have been carried out for tokamak and ST experiments which exhibit internal transport barriers (ITB) and good plasma confinement. Qualitative correlation is found for improved confinement before and during ITB plasmas on Alcator C-Mod [2] and NSTX [3], with weaker long wavelength micro-instabilities in the plasma core regions. Mixing length transport models are discussed. The NSTX L-mode is found to be near marginal stability for kinetic ballooning modes. Fully electromagnetic, linear, gyrokinetic calculations of the Alcator C-Mod ITB during off-axis rf heating, following four plasma species and including the complete electron response show ITG/TEM microturbulence is suppressed in the plasma core and in the barrier region before barrier formation, without recourse to the usual requirements of velocity shear or reversed magnetic shear [4-5]. No strongly growing long or short wavelength drift modes are found in the plasma core but strong ITG/TEM and ETG drift wave turbulence is found outside the barrier region. Linear microstability analysis is qualitativelymore » consistent with the experimental transport analysis, showing low transport inside and high transport outside the ITB region before barrier formation, without consideration of ExB shear stabilization.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., Princeton, NJ (US)
Sponsoring Org.:
USDOE; USDOE Office of Science (SC) (US)
OSTI Identifier:
841196
Report Number(s):
PPPL-4083
TRN: US0502399
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 20 Jun 2005
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BENCHMARKS; CONFINEMENT; ELECTRONS; FLUCTUATIONS; HEATING; KINETICS; PHYSICS; PLASMA CONFINEMENT; SHEAR; STABILITY; STABILIZATION; TESTING; TURBULENCE; VELOCITY; WAVELENGTHS; COMPUTER SIMULATION; GYROKINETIC EQUATIONS; TOKAMAKS, NSTX

Citation Formats

M.H. Redi, W. Dorland, C.L. Fiore, D. Stutman, J.A. Baumgaertel, B. Davis, S.M. Kaye, D.C. McCune, J. Menard, and G. Rewoldt. Testing Gyrokinetics on C-Mod and NSTX. United States: N. p., 2005. Web. doi:10.2172/841196.
M.H. Redi, W. Dorland, C.L. Fiore, D. Stutman, J.A. Baumgaertel, B. Davis, S.M. Kaye, D.C. McCune, J. Menard, & G. Rewoldt. Testing Gyrokinetics on C-Mod and NSTX. United States. doi:10.2172/841196.
M.H. Redi, W. Dorland, C.L. Fiore, D. Stutman, J.A. Baumgaertel, B. Davis, S.M. Kaye, D.C. McCune, J. Menard, and G. Rewoldt. Mon . "Testing Gyrokinetics on C-Mod and NSTX". United States. doi:10.2172/841196. https://www.osti.gov/servlets/purl/841196.
@article{osti_841196,
title = {Testing Gyrokinetics on C-Mod and NSTX},
author = {M.H. Redi and W. Dorland and C.L. Fiore and D. Stutman and J.A. Baumgaertel and B. Davis and S.M. Kaye and D.C. McCune and J. Menard and G. Rewoldt},
abstractNote = {Quantitative benchmarks of computational physics codes against experiment are essential for the credible application of such codes. Fluctuation measurements can provide necessary critical tests of nonlinear gyrokinetic simulations, but such require extraordinary computational resources. Linear micro-stability calculations with the GS2 [1] gyrokinetic code have been carried out for tokamak and ST experiments which exhibit internal transport barriers (ITB) and good plasma confinement. Qualitative correlation is found for improved confinement before and during ITB plasmas on Alcator C-Mod [2] and NSTX [3], with weaker long wavelength micro-instabilities in the plasma core regions. Mixing length transport models are discussed. The NSTX L-mode is found to be near marginal stability for kinetic ballooning modes. Fully electromagnetic, linear, gyrokinetic calculations of the Alcator C-Mod ITB during off-axis rf heating, following four plasma species and including the complete electron response show ITG/TEM microturbulence is suppressed in the plasma core and in the barrier region before barrier formation, without recourse to the usual requirements of velocity shear or reversed magnetic shear [4-5]. No strongly growing long or short wavelength drift modes are found in the plasma core but strong ITG/TEM and ETG drift wave turbulence is found outside the barrier region. Linear microstability analysis is qualitatively consistent with the experimental transport analysis, showing low transport inside and high transport outside the ITB region before barrier formation, without consideration of ExB shear stabilization.},
doi = {10.2172/841196},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 20 00:00:00 EDT 2005},
month = {Mon Jun 20 00:00:00 EDT 2005}
}

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