Steady State RF-Current Drive Theory Based upon the Relativistic Fokker-Planck Equation with Quasilinear Diffusion

A simple analytic- treatment based upon the moments of the relativistic two-dimensional Fokker-Planck equation combined with resonant quasilinear diffusion is used to describe steady-state RF current drive by waves. For RF diffusion parallel to the magnetic field (as in lower-hybrid current drive) it is shown that current carried by high parallel momenta must have an associated high averaged perpendicular energy. The model is also applied to unidirectional perpendicular RF diffusion which is relevant to electron cyclotron current drive. I I