Electron cyclotron absorption by RF driven current-carrying plasmas with fast particle losses

Abstract

We use quasilinear theory to investigate the influence of losses of energetic particles on the behaviour of electron cyclotron absorption during lower hybrid plus electron cyclotron current drive. Our analysis takes into account the quasilinear effects of the interaction of electron cyclotron radiation with a lower hybrid produced tail in the presence of collisions and a loss term for energetic particles. We study the behaviour of different quantities, as the parallel electron distribution function and the perpendicular temperature, for several values of the electron confinement time, an important parameter of the model loss term. The absorption of extraordinary mode electron cyclotron waves by tail electrons results to be substantially reduced when the loss term is taken into account in the quasilinear diffusion equation, as compared to the case where these losses are neglected.