SUPRATHERMAL ELECTRONS IN VERSATOR, TORE-SUPRA AND TDEV AS SEEN BY ELECTRON-CYCLOTRON ABSORPTION DIAGNOSTICS

A review of the procedures which have been developed to measure suprat hermal electron distribution functions is given. These experiments hav e been conducted on three tokamaks; Versator, Tore Supra and TdeV. The absorption of an electron cyclotron wave is measured at frequencies b elow the fundamental cyclotron frequency. Theory relates this absorpti on to the amplitude of the distribution function. Experimentally, refr active losses must be separated from absorption losses and contaminati on of the data by reflections within the system must be avoided. Illus trative results from each tokamak are presented.