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

Monte Carlo operators for the orbit-averaged Fokker-Planck equation describing collisions and wave-particle interaction are constructed. Special emphasis is put on ion-cyclotron-resonance heating of tokamaks, but the results are applicable to general quasilinear processes in arbitrary 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 for simulating, e.g., radio-frequency heating, wave-driven spatial diffusion, and alpha particle slowing down.