The stochastic nature of ion-cyclotron-resonance wave--particle interaction in tokamaks
- Institute for Electromagnetic Field Theory and Plasma Physics, Chalmers University of Technology, S-412 96 Goeteborg (Sweden)
The threshold in wave amplitude for the onset of stochastic motion of ion-cyclotron-resonance-heated minority ions in tokamaks is calculated. As a separate result, the solutions to the guiding center equations of motion are presented. Full account is taken to the effects of the finite orbit width of high-energy particles and the ellipticity of the flux surfaces. The orbits of trapped particles are shown to become stochastic more easily than those of circulating particles, and near the trapped/passing boundary an arbitrarily weak wave field is needed for stochastization. Finite orbit width effects have significant impact on the results, decreasing the stochastization amplitude for highly energetic particles considerably, as compared with earlier theories. Nevertheless, for realistic JET parameters (Plasma Phys. Controlled Fusion {bold 30}, 1467 (1988)), only a small fraction of the minority ions move stochastically in a monochromatic ion-cyclotron range of frequencies (ICRF) wave field.
- OSTI ID:
- 7105224
- Journal Information:
- Physics of Fluids B; (United States), Vol. 4:7; ISSN 0899-8221
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
TOKAMAK DEVICES
ION CYCLOTRON-RESONANCE
STOCHASTIC PROCESSES
AMPLITUDES
FINITE DIFFERENCE METHOD
LARMOR RADIUS
ORBITS
CLOSED PLASMA DEVICES
CYCLOTRON RESONANCE
ITERATIVE METHODS
NUMERICAL SOLUTION
RESONANCE
THERMONUCLEAR DEVICES
700310* - Plasma Confinement- (1992-)