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Title: Quasi-linear gyrokinetic predictions of the Coriolis momentum pinch in NSTX

Abstract

This paper presents quasi-linear gyrokinetic predictions of the Coriolis momentum pinch for low aspect-ratio NSTX H-modes where previous experimental measurements were focused. Local, linear calculations predict that in the region of interest (just outside the mid-radius) of these relatively high-beta plasmas, profiles are most unstable to microtearing modes that are only effective in transporting electron energy. However, sub-dominant electromagnetic and electrostatic ballooning modes are also unstable, which are effective at transporting energy, particles and momentum. The quasi-linear prediction of transport from these weaker ballooning modes, assuming they contribute transport in addition to that from microtearing modes in a nonlinear turbulent state, leads to a very small or outward convection of momentum, inconsistent with the experimentally measured inward pinch, and opposite to predictions in conventional aspect ratio tokamaks. Additional predictions of a low beta L-mode plasma, unstable to more traditional electrostatic ion temperature gradient-trapped electron mode instability, show that the Coriolis pinch is inward but remains relatively weak and insensitive to many parameter variations. The weak or outward pinch predicted in NSTX plasmas appears to be at least partially correlated to changes in the parallel mode structure that occur at finite beta and low aspect ratio, as discussed in previous theories.more » The only conditions identified where a stronger inward pinch is predicted occur either in the purely electrostatic limit or if the aspect ratio is increased. As the Coriolis pinch cannot explain the measured momentum pinch, additional theoretical momentum transport mechanisms are discussed that may be potentially important.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1366495
DOE Contract Number:  
AC02-09CH11466
Resource Type:
Data
Resource Relation:
Related Information: Physics of Plasmas, Vol 23, p.052508 (May 2016)
Data Type:
Figures/Plots
Country of Publication:
United States
Language:
English
Subject:
Tokamak Turbulence Transport Momentum pinch

Citation Formats

Guttenfelder, W., Kaye, S. M., Ren, Y., Solomon, W., Bell, R. E., Candy, J., Gerhardt, S. P., LeBlanc, B. P., and Yuh, H. Quasi-linear gyrokinetic predictions of the Coriolis momentum pinch in NSTX. United States: N. p., 2016. Web. doi:10.11578/1366495.
Guttenfelder, W., Kaye, S. M., Ren, Y., Solomon, W., Bell, R. E., Candy, J., Gerhardt, S. P., LeBlanc, B. P., & Yuh, H. Quasi-linear gyrokinetic predictions of the Coriolis momentum pinch in NSTX. United States. doi:10.11578/1366495.
Guttenfelder, W., Kaye, S. M., Ren, Y., Solomon, W., Bell, R. E., Candy, J., Gerhardt, S. P., LeBlanc, B. P., and Yuh, H. Fri . "Quasi-linear gyrokinetic predictions of the Coriolis momentum pinch in NSTX". United States. doi:10.11578/1366495. https://www.osti.gov/servlets/purl/1366495.
@article{osti_1366495,
title = {Quasi-linear gyrokinetic predictions of the Coriolis momentum pinch in NSTX},
author = {Guttenfelder, W. and Kaye, S. M. and Ren, Y. and Solomon, W. and Bell, R. E. and Candy, J. and Gerhardt, S. P. and LeBlanc, B. P. and Yuh, H.},
abstractNote = {This paper presents quasi-linear gyrokinetic predictions of the Coriolis momentum pinch for low aspect-ratio NSTX H-modes where previous experimental measurements were focused. Local, linear calculations predict that in the region of interest (just outside the mid-radius) of these relatively high-beta plasmas, profiles are most unstable to microtearing modes that are only effective in transporting electron energy. However, sub-dominant electromagnetic and electrostatic ballooning modes are also unstable, which are effective at transporting energy, particles and momentum. The quasi-linear prediction of transport from these weaker ballooning modes, assuming they contribute transport in addition to that from microtearing modes in a nonlinear turbulent state, leads to a very small or outward convection of momentum, inconsistent with the experimentally measured inward pinch, and opposite to predictions in conventional aspect ratio tokamaks. Additional predictions of a low beta L-mode plasma, unstable to more traditional electrostatic ion temperature gradient-trapped electron mode instability, show that the Coriolis pinch is inward but remains relatively weak and insensitive to many parameter variations. The weak or outward pinch predicted in NSTX plasmas appears to be at least partially correlated to changes in the parallel mode structure that occur at finite beta and low aspect ratio, as discussed in previous theories. The only conditions identified where a stronger inward pinch is predicted occur either in the purely electrostatic limit or if the aspect ratio is increased. As the Coriolis pinch cannot explain the measured momentum pinch, additional theoretical momentum transport mechanisms are discussed that may be potentially important.},
doi = {10.11578/1366495},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Apr 01 00:00:00 EDT 2016},
month = {Fri Apr 01 00:00:00 EDT 2016}
}

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Works referencing / citing this record:

Quasi-linear gyrokinetic predictions of the Coriolis momentum pinch in National Spherical Torus Experiment
journal, May 2016

  • Guttenfelder, W.; Kaye, S. M.; Ren, Y.
  • Physics of Plasmas, Vol. 23, Issue 5, Article No. 052508
  • DOI: 10.1063/1.4948791