J. Carlsson et al., THE EFFECT OF THE TOROIDAL WAVE-NUMBER SPECTRUM ON THE HIGH-ENERGY TAIL FORMATION DURING ICRH, Nuclear fusion, 37(6), 1997, pp. 719-723
The influence of finite orbit width effects and wave induced spatial d
iffusion on the resonant ion distribution function in the presence of
ion cyclotron resonance heating (ICRH) is studied. In particular, it i
s found that the toroidal wavenumber spectrum affects the fast ion ene
rgy density and the local formation of the high energy tail. I;br high
energy ions interacting with waves having a large toroidal wavenumber
, the wave induced spatial diffusion plays an equal or even more impor
tant role than the finite orbit width. Only in the limit of artificial
ly high plasma current and low toroidal wavenumber are results from tw
o dimensional (2-D) orbit averaged Fokker-Planck models recovered. The
finite orbit width and the wave induced spatial diffusion also produc
e ions that follow loss orbits, resulting in localized high energy ion
s losses to the wall.