Parametric study of alpha-particle heating in tokamaks

A Monte-Carlo alpha-particle orbit code was used to calculate the alpha-particle heating profiles in tokamaks. A number of parameters have been varied (plasma current, aspect ratio, current density profile, electron density and temperature profiles, and alpha-particle limiter location) and their influence on the heating profiles has been discussed. The alpha-particle orbit code uses a Monte-Carlo particle simulation algorithm: the transport of all the alpha-particles in a tokamak is simulated by following the motion of a carefully chosen sample of particles which are selected from the alpha-particle distribution. Quantities which would ordinarily be expressed as integrals over the distribution function are evaluated by summing over the sample population. The dynamics of the alpha-particle ensemble are thus reduced to single-particle equations of motion