Toroidal coupling of disparate helical tearing modes

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860844· OSTI ID:6241429

Li, D; Huo, Y ^[1]

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1. Institute of Plasma Physics, Academia Sinica, P.O. Box 1126, Hefei 230031 (China)

An analytical model has been developed for toroidal coupling of tearing modes with different helicities in the low-[beta] and large aspects ratio tokamaks. A standard characteristic value problem has been naturally composed according to the structure of magnetohydrodynamic (MHD) solutions. The explicit general dispersion relation has been obtained by the asymptotic matching. The growth rates (characteristic values) and corresponding flux perturbations (characteristic functions) of the toroidal tearing mode have been derived. The toroidal coupling plays a role mainly through the correction for the ideal MHD solutions. Without loss of generality, variation tendency of growth rates has been analyzed for a toroidal tearing mode with cylindrical components [ital m]/[ital n] and ([ital m]+1)/[ital n], the results indicate that (1) The toroidal coupling has a destabilizing effect on the tearing modes; (2) the beating'' of the growth rates of two components leads to strong coupling, even if the coupling parameter [ital C] is quite small, and the coupling effect does not explicitly rely on magnitude of [Delta][sup [prime](0)][sub [ital m]] of cylindrical component, so that [Delta][sup [prime](0)][sub [ital m]] [similar to] [epsilon] is neither a necessary nor sufficient condition for strong coupling.

• OSTI ID: 6241429
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 5:10; ISSN 0899-8221; ISSN PFBPEI
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
ANNULAR SPACE
ASYMPTOTIC SOLUTIONS
CLOSED CONFIGURATIONS
CLOSED PLASMA DEVICES
CONFIGURATION
DISPERSION RELATIONS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
INSTABILITY GROWTH RATES
LOW-BETA PLASMA
MAGNETIC FIELD CONFIGURATIONS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
PARTICLE MODELS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SPACE
STRONG-COUPLING MODEL
TEARING INSTABILITY
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOROIDAL CONFIGURATION