A 1D quasilinear equation describing the current drive excitation by helicons in a tokamak plasma

A quasilinear equation which allows describing evolution of the electron distribution function and generation of non-inductive currents by helicons is obtained. It is shown that in the analyzed case the Fokker-Planck equation can be approximated by a one-dimensional equation in the longitudinal electron velocity space with a diffusion coefficient proportional to the helicon power absorbed by electrons due to Landau damping.