Drift kinetic theory of neoclassical tearing modes in a low collisionality tokamak plasma: magnetic island threshold physics

Abstract This paper reviews the effects of resonant magnetic perturbation (RMP) on classical tearing modes (TMs) and neoclassical tearing modes (NTMs) from the theory, experimental discovery and numerical results with a focus on four major aspects: (i) mode mitigation, where the TM/NTM is totally suppressed or partly mitigated by the use of RMP; (ii) mode penetration, which means a linearly stable TM/NTM triggered by the externally applied RMP; (iii) mode locking, namely an existing rotating magnetic island braked and finally stopped by the RMP; (iv) mode unlocking, as the name suggests, it is the reverse of the mode locking process. The key mechanism and physical picture of above phenomena are revealed and summarized.

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A neoclassical drift-magnetohydrodynamical fluid model of the interaction of a magnetic island chain with a resonant error-field in a high temperature tokamak plasma

Physics of Plasmas ◽

10.1063/1.5022685 ◽

2018 ◽

Vol 25 (4) ◽

pp. 042503 ◽

Cited By ~ 1

Author(s):

Richard Fitzpatrick

Keyword(s):

High Temperature ◽

Fluid Model ◽

Tokamak Plasma ◽

Magnetic Island ◽

Error Field

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Neoclassical tearing modes for a finite ratio of ion gyroradius to magnetic island width

Plasma Physics and Controlled Fusion ◽

10.1088/0741-3335/43/8/308 ◽

2001 ◽

Vol 43 (8) ◽

pp. 1149-1155 ◽

Cited By ~ 5

Author(s):

S V Konovalov ◽

A B Mikhailovskii

Keyword(s):

Magnetic Island ◽

Tearing Modes

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The influence of the ion polarization current on magnetic island stability in a tokamak plasma

Physics of Plasmas ◽

10.1063/1.2402914 ◽

2006 ◽

Vol 13 (12) ◽

pp. 122507 ◽

Cited By ~ 43

Author(s):

R. Fitzpatrick ◽

F. L. Waelbroeck ◽

F. Militello

Keyword(s):

Tokamak Plasma ◽

Polarization Current ◽

Magnetic Island

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Linear kinetic theory of high-m tearing modes

The Physics of Fluids ◽

10.1063/1.862880 ◽

1980 ◽

Vol 23 (10) ◽

pp. 2022 ◽

Cited By ~ 16

Author(s):

M. Rosenberg ◽

R. R. Dominguez ◽

W. Pfeiffer ◽

R. E. Waltz

Keyword(s):

Kinetic Theory ◽

Tearing Modes ◽

Linear Kinetic ◽

Linear Kinetic Theory

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The effect of biased limiter on the magnetic island width in tokamak plasma

Journal of Plasma Physics ◽

10.1017/s0022377813001190 ◽

2013 ◽

Vol 80 (1) ◽

pp. 113-130 ◽

Cited By ~ 2

Author(s):

M. Ghasemloo ◽

M. Ghoranneviss ◽

M. K. Salem

Keyword(s):

Negative Polarity ◽

Singular Value ◽

Tokamak Plasma ◽

Plasma Stability ◽

Minimal Effect ◽

Positive Polarity ◽

Magnetic Islands ◽

Magnetic Island ◽

Wavelet Techniques ◽

Value Decomposition

AbstractIn this work the effects of Cold Biased Limiter (CBL) and Emissive Biased Limiter (EBL) have been individually investigated, in both positive and negative polarities, on the width and frequency of magnetic islands. The effects were examined using singular value decomposition and wavelet techniques on mirnov coil signals. The results show that the application of EBL with both positive and negative polarities has been more effective on plasma stability compared with CBL. Comparing different polarities of CBL and EBL revealed that the positive polarity was more effective on the width of magnetic islands than negative polarity. The greatest impact occurs during EBL with positive polarity, in which reduction is observed in both width of magnetic islands and emission of Hα radiation. Besides, intensity and frequency of magnetic islands are reduced from 50 to 25 kHz in around 1 ms after bias application. Meanwhile, the minimal effect on width and frequency of magnetic field occurs in CBL with negative polarity.

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