Nonlinear destabilization of linearly stable tearing modes with multiple rational surfaces

Journal Article · Sun May 01 00:00:00 EDT 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870723· OSTI ID:6686590

Persson, M; Dewar, R L ^[1]

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1. Department of Theoretical Physics and Plasma Research Laboratory, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, A.C.T. 0200 (Australia)

The stability of finite size magnetic islands is analyzed in configurations with multiple resonant magnetic surfaces. It is demonstrated that there are configurations that are linearly stable which can be unstable to finite size perturbations. Two different examples of single helicity double tearing are given for configurations with two [ital q]=2 surfaces. In the first case the destabilization is due to the extension of magnetic separatrices out to regions of destabilizng current gradients. For the second case the modes are linearly stabilized by the suppression of the linear coupling of the rational surfaces by differential plasma rotation, which essentially decouples the perturbations around the different rational surfaces. A finite size magnetic island will interact quasilinearly with initial plasma rotation. The plasma rotation is then equilibrated and the mode destabilized.

• OSTI ID: 6686590
• Journal Information: Physics of Plasmas; (United States), Vol. 1:5; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
MAGNETIC ISLANDS
TEARING INSTABILITY
INSTABILITY GROWTH RATES
MAGNETOHYDRODYNAMICS
PERTURBATION THEORY
ROTATING PLASMA
TOKAMAK DEVICES
CLOSED PLASMA DEVICES
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MECHANICS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES
700340* - Plasma Waves
Oscillations
& Instabilities- (1992-)