Fast ray tracing code for LCHD simulations

A new numerical code for LHCD simulations is described. The code uses the standard simulation model based on combined ray tracing and Fokker-Planck calculations; however, its performance is improved considerably by modification of the numerical concept. In particular, the speed is enhanced by two orders of magnitude and any required number of iterations necessary for finding a self-consistent solution is feasible. The code predicted electron distribution function and quasi-linear diffusion coefficient are compared with an analytical solution in the important transition region close to the lower end of the plateau. The relation between the simulation results and the general ray dynamics is discussed.