Nonlinear interaction of tearing modes: A comparison between the tokamak and the reversed field pinch configurations

Journal Article · Tue Jan 01 04:00:00 EST 1985 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.865194· OSTI ID:6144880

Holmes, J A; Carreras, B A; Hender, T C; Hicks, H R; Lynch, V E; An, Z G; Diamond, P H

The multiple helicity nonlinear interaction of resistive tearing modes is compared for the tokamak and reversed field pinch configurations using the magnetohydrodynamic equations. Unlike the case of the tokamak disruption, for which this interaction is destabilizing when islands overlap, the nonlinear coupling of the dominant helicities is shown to be a stabilizing influence in the reversed field pinch. The behavior of the coupled instabilities in the two configurations can be understood as a consequence of the stability properties of the nonlinearly driven modes. In the case of the tokamak disruption, quasilinear effects linearly destabilize the dominant driven mode, which then feeds energy to the driving mode. For the reversed field pinch the driven modes remain stable, acting as a brake on the growth of the dominant instabilities. Furthermore, for the reversed field pinch configuration, numerical results indicate that nonlinear coupling of different helicities results in noticeably more rapid saturation of the dominant instabilities than was observed in single helicity studies.

• Research Organization: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6144880
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 28:1; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107 -- Fusion Energy-- Plasma Research-- Instabilities
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
CLOSED PLASMA DEVICES
CORRELATIONS
FLUID MECHANICS
HELICITY
HYDRODYNAMICS
INSTABILITY
MAGNETOHYDRODYNAMICS
MECHANICS
NONLINEAR PROBLEMS
PARTICLE PROPERTIES
PINCH EFFECT
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
REVERSE-FIELD PINCH
TEARING INSTABILITY
THERMONUCLEAR DEVICES
TOKAMAK DEVICES