Measured improvement of global magnetohydrodynamic mode stability at high-beta, and in reduced collisionality spherical torus plasmas

被引：12

作者：

Berkery, J. W. ^{[1
]}

Sabbagh, S. A. ^{[1
]}

Balbaky, A. ^{[1
]}

Bell, R. E. ^{[2
]}

Betti, R. ^{[3
]}

Diallo, A. ^{[2
]}

Gerhardt, S. P. ^{[2
]}

LeBlanc, B. P. ^{[2
]}

Manickam, J. ^{[2
]}

Menard, J. E. ^{[2
]}

Podesta, M. ^{[2
]}

机构：

[1] Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA

[2] Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA

[3] Univ Rochester, Laser Energet Lab, Rochester, NY 14623 USA

来源：

PHYSICS OF PLASMAS | 2014年 / 21卷 / 05期

关键词：

2ND REGION; STABILIZATION;

D O I：

10.1063/1.4876610

中图分类号：

O35 [流体力学]; O53 [等离子体物理学];

学科分类号：

070204 ; 080103 ; 080704 ;

摘要：

Global mode stability is studied in high-beta National Spherical Torus Experiment (NSTX) plasmas to avoid disruptions. Dedicated experiments in NSTX using low frequency active magnetohydrodynamic spectroscopy of applied rotating n = 1 magnetic fields revealed key dependencies of stability on plasma parameters. Observations from previous NSTX resistive wall mode (RWM) active control experiments and the wider NSTX disruption database indicated that the highest beta(N) plasmas were not the least stable. Significantly, here, stability was measured to increase at beta(N)/l(i) higher than the point where disruptions were found. This favorable behavior is shown to correlate with kinetic stability rotational resonances, and an experimentally determined range of measured E x B frequency with improved stability is identified. Stable plasmas appear to benefit further from reduced collisionality, in agreement with expectation from kinetic RWM stabilization theory, but low collisionality plasmas are also susceptible to sudden instability when kinetic profiles change. (C) 2014 AIP Publishing LLC.

引用

页数：6

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