Linear stability of low mode number tearing modes in the banana collisionality regime

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Physics of Fluids B: Plasma Physics; (USA)

DOI:https://doi.org/10.1063/1.859173· OSTI ID:5174849

Fitzpatrick, R ^[1]

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1. Culham Laboratory (Euratom/UKAEA Fusion Association), Abingdon, OX14 3DB, England (GB)

The semicollisional layer equations governing the linear stability of small mode number tearing modes in a low beta, large aspect ratio, tokamak equilibrium are derived from an expansion of the gyrokinetic equation. In this analysis only the cases where the ion Larmor radius is either much less than, or much greater than, the layer width are considered. Both the electrons and the ions are assumed to lie in the banana collisionality regime. One interesting feature of the derived layer equations, in the limit of small ion Larmor radius, is a substantial reduction in the effective collisionality of the system due to neoclassical ion dynamics. Next, using a shooting code, a dispersion relation is obtained from the layer equations in the limits of small ion Larmor radius and a vanishingly small fraction of trapped particles. As expected, strong semicollisional stabilization of the mode is found, but, in addition, a somewhat weaker destabilizing effect is obtained in the transition region between the collisional and semicollisional regimes.

• OSTI ID: 5174849
• Journal Information: Physics of Fluids B: Plasma Physics; (USA), Vol. 1:12; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
LOW-BETA PLASMA
TEARING INSTABILITY
TOKAMAK DEVICES
PLASMA CONFINEMENT
ASPECT RATIO
BANANA REGIME
COLLISIONAL PLASMA
CYLINDRICAL CONFIGURATION
EQUILIBRIUM
IONS
LARMOR RADIUS
STABILITY
CHARGED PARTICLES
CLOSED PLASMA DEVICES
CONFIGURATION
CONFINEMENT
INSTABILITY
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES
TRAPPING
700107* - Fusion Energy- Plasma Research- Instabilities