Calculation of Fokker-Planck Ion Distributions Resulting from ICRF Full-Wave Code Fields and Collisions

A fully numerical calculation of ion velocity and spatial diffusion coefficients resulting from full wave code electromagnetic fields in tokamak geometry, has been implemented. EM fields are obtained from the TORIC and AORSA-2D codes. The described coefficient calculator integrates the unapproximated Lorentz equation of motion to obtain the change in velocity after one complete transit of the noncircular tokamak flux surfaces. Averaging velocity changes over initial starting gyro-phase and initial toroidal angle of an ion, gives bounce-averaged diffusion coefficients. Performing this operation for an array of initial parallel and perpendicular velocities and radial locations gives the full set of coefficients. Coupling the coefficients to the CQL3D Fokker-Planck code enables calculation of the equilibrium nonthermal ion distribution function resulting from the EM fields and collisions. This calculation is computationally feasible due to the recent rapid advances of computing hardware. Adequate resolution is obtained in 50 CPU hours. Initial results will be presented, and compared with a Fokker-Planck/ray-tracing calculation