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, i n s i t u calibration technique enables the determination of the profile of the plasma electron temperature from the fundamental ordinary mode and second harmonic extraordinary mode cyclotron emission intensity, with an accuracy of better than 10%. Temperature measurements made with the scanning receivers agree well with data from laser TV Thomson scattering and x‐ray pulse‐height analysis measurements. The time evolution of the temperature profile during temperature sawteeth fluctuations is well documented when the period of the fluctuation (30–100 ms) is much longer than the instrument sweep repetition time.