Electron temperature measurements by microwave transmission in Tore Supra

A new application of electron cyclotron absorption (ECA) as a direct measurement of the electron temperature profile is proposed and the implementation and experimental test of this method on the Tore Supra tokamak is discussed (at this stage limited to the determination of the central temperature). The method consists in measuring the optical depth of waves propagating along vertical chords, at frequencies close to the electron-cyclotron frequency or its first harmonics. Sweeping the wave frequency, the full absorption line can be measured. In a large and hot tokamak plasma, the width of the absorption line is proportional to the maximum electron temperature along the probing chord, which allows, in principle, the measurement of the full temperature profile if several chords are available. (K.A.) 13 refs.; 4 figs