Model Description of Alpha-Particle Stochastic Losses in a Toroidal Plasma

The distribution function of alpha particles in toroidal magnetic systems is found. Energy losses are considered, and the pitch-angle scattering is modeled by a Bathagor-Gross-Krook operator. Stochastic diffusion is accounted for by assuming that toroidally trapped particles immediately exit the device. It is found that the energy loss of transit alpha particles in the presence of effective loss is not crucial, so the energy is well transferred into the bulk plasma.