Alpha particle effects on the internal kink and fishbone modes
- Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08540 (United States)
The effects of alpha particles on the internal kink and fishbone modes are studied analytically. The nonadiabatic contribution from untrapped alpha particles is negligible. Finite inverse aspect ratio, plasma [beta], and plasma shaping effects can significantly enhance the trapped particle drift reversal domain in the pitch angle space and reduce the bounce-averaged magnetic drift frequency. The decrease of the drift magnitude and drift reversal effects on the ideal kink mode is small, but the [beta][sub [alpha]] threshold for the fishbone mode can be much lower than previously predicted [B. Coppi, S. Migliuolo, F. Pegoraro, and F. Porcelli, Phys. Fluids B [bold 2], 927 (1990)]. Moreover, the fishbone mode could be excited by alpha particles, even when the plasma is stable in the ideal magnetohydrodynamic (MHD) limit. In addition, the ion diamagnetic drift frequency (finite ion Larmor radius effect) has a strong destabilizing effect on the fishbone mode when it is comparable with the trapped alpha-averaged precessional drift frequency, even though it stabilizes the plasma in the ideal MHD limit.
- DOE Contract Number:
- AC02-76CH03073
- OSTI ID:
- 6959012
- Journal Information:
- Physics of Plasmas; (United States), Journal Name: Physics of Plasmas; (United States) Vol. 1:10; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
ALPHA PARTICLES
ASPECT RATIO
CHARGED PARTICLES
CLOSED PLASMA DEVICES
DISPERSION RELATIONS
FISHBONE INSTABILITY
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
KINK INSTABILITY
LARMOR RADIUS
LOW-BETA PLASMA
MAGNETOHYDRODYNAMICS
MECHANICS
PLASMA
PLASMA DRIFT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRAPPED-PARTICLE INSTABILITY