A review of ECRH experiments

Abstract

The absorption of electron cyclotron waves in the electron component of the plasma in both tokamaks and stellarators has led to most interesting results on energy confinement and instability control. The ability to heat the electrons in a relatively localised region has enabled the electron temperature profile and thereby the current profile to be modified allowing the stabilisation of the m=1 and m=2 modes in the tokamak. Thermal transport has also been studied by this means with results now available on changes in tau E and on chi e using the power modulation technique. At low densities the formation of a high energy tail accompanies an increase in tau E. At high densities tau E decreases with power but for heating on axis the value of tau E lies above that of L mode scaling. In the stellarator diffusion due to collisions is adequate to explain thermal transport in the inner regions of low density ECRH discharges.