Stabilization of external kink modes in a tokamak with rotating plasma

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Plasma Physics Reports

OSTI ID:172261

Mikhailovskii, A B; Kuvshinov, B N ^[1]

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1. Institute of Nuclear Fusion, Kurchatov Institute Russian Research Centre, pl. Kurchatova, Moscow, 123182 (Russian Federation)

An analytical theory of stabilization of external kink modes in a tokamak with rotating plasma is developed, which is of interest in connection with experiments on the DIII-D tokamak demonstrating such a stabilization. It is assumed that, in addition to the main poloidal harmonic, the mode includes one or more side-band poloidal harmonics with singular points lying inside the plasma. Near these singular points, plasma inertia and related toroidal effects, the compressible part of plasma pressure and longitudinal viscosity, are allowed for. These effects are described kinetically taking into account the toroidal trapping of the resonant ions, which is essential if the toroidal velocity is small compared to the ion thermal velocity. Thereby, the theory presented includes both ion Landau damping and its weakening due to toroidal trapping. Near the singular points high-beta effects, which result in the finiteness of the Mercier index {ital s}, are allowed for. It is shown that the influence of plasma rotation on the external kink modes is most significant in the case of {ital s}{lt}0, i.e., when the development of the instability in a non-rotating plasma is most highly favored. In this case, the plasma rotation plays a stabilizing role, even when the ion Landau damping is neglected. The analysis presented also confirms the hypothesis of Bondeson and Ward on the stabilizing effect of ion Landau damping if this damping is not too small.

• OSTI ID: 172261
• Journal Information: Plasma Physics Reports, Journal Name: Plasma Physics Reports Journal Issue: 10 Vol. 21; ISSN PPHREM; ISSN 1063-780X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANALYTICAL SOLUTION
KINK INSTABILITY
LANDAU DAMPING
MHD EQUILIBRIUM
ROTATING PLASMA
STABILIZATION
TOKAMAK DEVICES
TRAPPING