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Title: Large-mode-number magnetohydrodynamic instability driven by sheared flows in a tokamak plasma with reversed central shear

Abstract

The effect of a narrow sub-Alfvenic shear flow layer near the minimum q{sub min} of the tokamak safety factor profile in a configuration with reversed central shear is analyzed. Sufficiently strong velocity shear gives rise to a broad spectrum of fast growing Kelvin-Helmholtz (KH)-like ideal magnetohydrodynamic modes with dominant mode numbers m,n{approx}10. Nonlinear simulations with finite resistivity show magnetic reconnection near ripples caused by KH-like vortices, the formation of turbulent structures, and a flattening of the flow profile. The KH modes are compared to double tearing modes that dominate at lower shearing rates. The possible application of these results in tokamaks with internal transport barrier is discussed.

Authors:
; ;  [1]
  1. Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)
Publication Date:
OSTI Identifier:
20960078
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 1; Other Information: DOI: 10.1063/1.2435319; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONFIGURATION; CONFINEMENT; LAYERS; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; NONLINEAR PROBLEMS; PLASMA; PLASMA SIMULATION; SAFETY; SHEAR; TEARING INSTABILITY; TOKAMAK DEVICES

Citation Formats

Bierwage, Andreas, Yu Qingquan, and Guenter, Sibylle. Large-mode-number magnetohydrodynamic instability driven by sheared flows in a tokamak plasma with reversed central shear. United States: N. p., 2007. Web. doi:10.1063/1.2435319.
Bierwage, Andreas, Yu Qingquan, & Guenter, Sibylle. Large-mode-number magnetohydrodynamic instability driven by sheared flows in a tokamak plasma with reversed central shear. United States. doi:10.1063/1.2435319.
Bierwage, Andreas, Yu Qingquan, and Guenter, Sibylle. Mon . "Large-mode-number magnetohydrodynamic instability driven by sheared flows in a tokamak plasma with reversed central shear". United States. doi:10.1063/1.2435319.
@article{osti_20960078,
title = {Large-mode-number magnetohydrodynamic instability driven by sheared flows in a tokamak plasma with reversed central shear},
author = {Bierwage, Andreas and Yu Qingquan and Guenter, Sibylle},
abstractNote = {The effect of a narrow sub-Alfvenic shear flow layer near the minimum q{sub min} of the tokamak safety factor profile in a configuration with reversed central shear is analyzed. Sufficiently strong velocity shear gives rise to a broad spectrum of fast growing Kelvin-Helmholtz (KH)-like ideal magnetohydrodynamic modes with dominant mode numbers m,n{approx}10. Nonlinear simulations with finite resistivity show magnetic reconnection near ripples caused by KH-like vortices, the formation of turbulent structures, and a flattening of the flow profile. The KH modes are compared to double tearing modes that dominate at lower shearing rates. The possible application of these results in tokamaks with internal transport barrier is discussed.},
doi = {10.1063/1.2435319},
journal = {Physics of Plasmas},
number = 1,
volume = 14,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}