MONTE-CARLO OPERATORS FOR ORBIT-AVERAGED FOKKER-PLANCK EQUATIONS

Monte Carlo operators for the orbit-averaged Fokker-Planck equation de scribing collisions and wave-particle interaction are constructed. Spe cial emphasis is put on ion-cyclotron-resonance heating of tokamaks, b ut the results are applicable to general quasilinear processes in arbi trary magnetic configurations in which particle motion is integrable. All effects of nonstandard orbit topology, such as large orbit widths, are fully taken into account. The Monte Carlo operators may be used f or simulating, e.g., radio-frequency heating, wave-driven spatial diff usion, and alpha particle slowing down.