Analysis of a quasilinear model for ion-cyclotron interactions in tokamaks

Abstract

The quasilinear diffusion coefficient deviates significantly from the lowest order Larmor radius scaling D ∝ v⊥2n. This is not only caused by the finite Larmor radius effects, but also by the inhomogeneous electric field polarisation and the changes of the guiding centre orbits. The regions with strong interaction and the boundaries for resonant interaction are identified. At these boundaries the quasilinear diffusion coefficient becomes discontinuous. A new Monte Carlo scheme has been developed to treat problems with discontinuous diffusion coefficients.