Numerical calculation of the electron distribution function with the goal of simulating a current drive

The numerical simulation of any kinetic problem associated with auxiliary plasma heating and current drive requires the solution of a Fokker-Planck type equation. One of the main numerical problems of the kinetic equation solution consists of the conservative formulation, which is not so trivial especially for the Coulomb operator. There is a number of tricks designed especially for avoiding the numerical instabilities, but these tricks are not so general and the problem still requests great care. The article presents the results of numerical simulations of some problem associated with producing the current drive by lower hybrid heating. The Fokker-Planck kinetic equation is solved by the finite difference method with the help of the developed FPTM code. We show the results of successful application of the developed code to the one specific problem with the appearance of a plateau on the distribution function in the resonance region