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Title: Role of Alfven instabilities in energetic ion transport

Abstract

Experiments with plasma heating by waves at the ion cyclotron resonance of a minority species have shown that the heating efficiency degrades above a certain power threshold. It is found that this threshold is due to the destabilization of shear Alfven waves, which causes loss of fast ions. There are two distinct regimes characterized by low q{sub a} and high q{sub a}. In the first case, the fast ion distribution created by ICRF, lies entirely inside r{sub q=1}, away from the location of global TAE. This situation leads to the formation of a very strong fast ion population which stabilizes the sawteeth, but also excites Energetic Particle Modes (EPM), which transport fast ions outside r{sub q=1} causing the giant crash. At higher q{sub a}, the widening of the Alfven gap due to the steeper q profile, brings the global TAE ''in contact'' with the fast ion distribution. This results in an immediate and continuous depletion of fast ions from the core, which prevents the formation of the monster sawtooth and the excitation of EPM. (c) 1999 American Institute of Physics.

Authors:
 [1];  [2];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08453 (United States)
  2. TRINITI, Troitsk, Moscow, Russia 142092 (Russian Federation)
Publication Date:
OSTI Identifier:
20216683
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 485; Journal Issue: 1; Other Information: PBD: 20 Sep 1999; Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ICR HEATING; ALFVEN WAVES; PLASMA INSTABILITY; DISPERSION RELATIONS; SAWTOOTH OSCILLATIONS

Citation Formats

Bernabei, S., Gorelenkov, N. N., Budny, R., Fredrickson, E. D., Hosea, J. C., Majeski, R., Phillips, C. K., and Wilson, J. R. Role of Alfven instabilities in energetic ion transport. United States: N. p., 1999. Web. doi:10.1063/1.59760.
Bernabei, S., Gorelenkov, N. N., Budny, R., Fredrickson, E. D., Hosea, J. C., Majeski, R., Phillips, C. K., & Wilson, J. R. Role of Alfven instabilities in energetic ion transport. United States. doi:10.1063/1.59760.
Bernabei, S., Gorelenkov, N. N., Budny, R., Fredrickson, E. D., Hosea, J. C., Majeski, R., Phillips, C. K., and Wilson, J. R. Mon . "Role of Alfven instabilities in energetic ion transport". United States. doi:10.1063/1.59760.
@article{osti_20216683,
title = {Role of Alfven instabilities in energetic ion transport},
author = {Bernabei, S. and Gorelenkov, N. N. and Budny, R. and Fredrickson, E. D. and Hosea, J. C. and Majeski, R. and Phillips, C. K. and Wilson, J. R.},
abstractNote = {Experiments with plasma heating by waves at the ion cyclotron resonance of a minority species have shown that the heating efficiency degrades above a certain power threshold. It is found that this threshold is due to the destabilization of shear Alfven waves, which causes loss of fast ions. There are two distinct regimes characterized by low q{sub a} and high q{sub a}. In the first case, the fast ion distribution created by ICRF, lies entirely inside r{sub q=1}, away from the location of global TAE. This situation leads to the formation of a very strong fast ion population which stabilizes the sawteeth, but also excites Energetic Particle Modes (EPM), which transport fast ions outside r{sub q=1} causing the giant crash. At higher q{sub a}, the widening of the Alfven gap due to the steeper q profile, brings the global TAE ''in contact'' with the fast ion distribution. This results in an immediate and continuous depletion of fast ions from the core, which prevents the formation of the monster sawtooth and the excitation of EPM. (c) 1999 American Institute of Physics.},
doi = {10.1063/1.59760},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 485,
place = {United States},
year = {1999},
month = {9}
}