Semi-analytical modelling of non-local ion-cyclotron resonance heating in toroidal geometry

A semi-analytical approach is proposed for computing the non-local response of a toroidal plasma to an electromagnetic perturbation. Although the perturbed distribution function as well as the absorbed power are also computed, the focus is on the associated quasi-linear diffusion operator. Different decorrelation models allow one to recapture the well-known ideal collisionless plasma result where the wave-particle energy exchange is exactly at resonance, as well as the more realistic plasma response where the interaction region is widened. The choice of the independent variables also allows one to carry out all computations except the integration of the guiding-centre motion analytically.