Fast scanning heterodyne receiver for the measurement of the time evolution of the electron temperature profile on the Tokamak Fusion Test Reactor

Two fast scanning heterodyne receivers, swept between 75-110 and 110-170 GHz in 2 ms every 4 ms, were developed to measure the electron cyclotron emission on the horizontal midplane of the Tokamak Fusion Test Reactor (TFTR) plasma. An absolute, in situ calibration technique enables the determination of the profile of the plasma electron temperature from the cyclotron emission intensity. The 4-ms repetition rate of the receiver allowed the resolution of "sawtooth" fluctuations of temperature, whose period was 10-100 ms, in profiles with central temperatures of 1-2.5 keV.