EFFECT OF PITCH-ANGLE SCATTERING ON THE DISTRIBUTION FUNCTION OF FASTFUSION PRODUCTS IN A TOKAMAK PLASMA

The results of a three dimensional (3-D) (in constants of motion space ) Fokker-Planck simulation of the steady state collisional behaviour o f fusion alphas in an axisymmetric TFTR-like tokamak plasma are presen ted. The distribution function of confined fusion products is shown to be strongly anisotropic and non-uniform in the radial co-ordinate. Th e influence of pitch angle scattering on distribution function anisotr opy is investigated. It is shown that the distribution function of fas t ions in the range where the cosine of the pitch angle is small is st rongly influenced by this scattering. A qualitative comparison of nume rical results and predictions of alpha particle distributions from pre vious studies is presented.