Impact of radial transport on the quasilinear plateau formation due to electron cyclotron wave absorption

Abstract

Numerical simulations using a three-dimensional Fokker–Planck code show that for small tokamaks the transport of electrons across the magnetic surfaces at a level consistent with anomalous transport has a large influence on the formation of the quasilinear plateau during electron cyclotron resonant heating. The reduction of wave absorption due to the plateau formation is much smaller when the effects of radial transport are included. This is explained by the localized nature of the resonance in velocity space and the strong dependence of resonant energy on radial position. Impact of the effect on diagnostic signals is discussed.