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Title: Trapped fast particle destabilization of internal kink mode for the locally flattened q-profile with an inflection point

Abstract

The destabilization of ideal internal kink modes by trapped fast particles in tokamak plasmas with a “shoulder”-like equilibrium current is investigated. It is found that energetic particle branch of the mode is unstable with the driving of fast-particle precession drifts and corresponds to a precessional fishbone. The mode with a low stability threshold is also more easily excited than the conventional precessional fishbone. This is different from earlier studies for the same equilibrium in which the magnetohydrodynamic (MHD) branch of the mode is stable. Furthermore, the stability and characteristic frequency of the mode are analyzed by solving the dispersion relation and comparing with the conventional fishbone. The results suggest that an equilibrium with a locally flattened q-profile, may be modified by localized current drive (or bootstrap current, etc.), is prone to the onset of the precessional fishbone branch of the mode.

Authors:
 [1]; ;  [2]
  1. Institute of Fusion Science, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)
  2. State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China)
Publication Date:
OSTI Identifier:
22600036
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BOOTSTRAP CURRENT; COMPARATIVE EVALUATIONS; DISPERSION RELATIONS; EQUILIBRIUM; MAGNETOHYDRODYNAMICS; PARTICLES; PLASMA; PRECESSION; STABILITY; TOKAMAK DEVICES; TRAPPING

Citation Formats

Wang, Xian-Qu, Zhang, Rui-Bin, and Meng, Guo. Trapped fast particle destabilization of internal kink mode for the locally flattened q-profile with an inflection point. United States: N. p., 2016. Web. doi:10.1063/1.4958645.
Wang, Xian-Qu, Zhang, Rui-Bin, & Meng, Guo. Trapped fast particle destabilization of internal kink mode for the locally flattened q-profile with an inflection point. United States. doi:10.1063/1.4958645.
Wang, Xian-Qu, Zhang, Rui-Bin, and Meng, Guo. Fri . "Trapped fast particle destabilization of internal kink mode for the locally flattened q-profile with an inflection point". United States. doi:10.1063/1.4958645.
@article{osti_22600036,
title = {Trapped fast particle destabilization of internal kink mode for the locally flattened q-profile with an inflection point},
author = {Wang, Xian-Qu and Zhang, Rui-Bin and Meng, Guo},
abstractNote = {The destabilization of ideal internal kink modes by trapped fast particles in tokamak plasmas with a “shoulder”-like equilibrium current is investigated. It is found that energetic particle branch of the mode is unstable with the driving of fast-particle precession drifts and corresponds to a precessional fishbone. The mode with a low stability threshold is also more easily excited than the conventional precessional fishbone. This is different from earlier studies for the same equilibrium in which the magnetohydrodynamic (MHD) branch of the mode is stable. Furthermore, the stability and characteristic frequency of the mode are analyzed by solving the dispersion relation and comparing with the conventional fishbone. The results suggest that an equilibrium with a locally flattened q-profile, may be modified by localized current drive (or bootstrap current, etc.), is prone to the onset of the precessional fishbone branch of the mode.},
doi = {10.1063/1.4958645},
journal = {Physics of Plasmas},
number = 7,
volume = 23,
place = {United States},
year = {Fri Jul 15 00:00:00 EDT 2016},
month = {Fri Jul 15 00:00:00 EDT 2016}
}