Publication

MHD characteristics in the high beta regime of the Large Helical Device

Wilfred Anthony Cooper
2001
Journal Articles

Abstract

The highest volume averaged beta values beta (t) of 2.2% at B-t = 0.75 T (gas puff) and 2.4% at D-t = 1.3 T (pellet) in helical devices have been achieved in LHD. The beta (t) dependence of MHD activities has been investigated in NBI plasmas. The n/m = 1/2 mode, excited in the core region, and the t = 1 resonant modes, in the peripheral region, have been observed. Both of the fluctuation amplitudes increase with beta (t) and pressure gradient. The strong n/m = 1/2 mode, which affects the plasma profile., has been observed in high beta (t) discharges, and the abrupt disappearance of the mode leads to restoration of the T-e profile. Violent instabilities which terminate the plasma and degradation of global energy confinement have not been observed so far.

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https://infoscience.epfl.ch/entities/publication/754d88d7-c56e-4e70-ab05-f39d5dcb138b

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Wilfred Anthony Cooper
2001
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/754d88d7-c56e-4e70-ab05-f39d5dcb138b

About this result

Related concepts (32)

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The stability of a plasma is an important consideration in the study of plasma physics. When a system containing a plasma is at equilibrium, it is possible for certain parts of the plasma to be disturbed by small perturbative forces acting on it. The stability of the system determines if the perturbations will grow, oscillate, or be damped out. In many cases, a plasma can be treated as a fluid and its stability analyzed with magnetohydrodynamics (MHD).

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MHD characteristics in the high beta regime of the Large Helical Device

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