ELECTRON-TEMPERATURE FLUCTUATION MEASUREMENT FROM ECE ON TEXT-U

The conceptual design and theory of diagnostics to measure electron temperature and density fluctuations using electron cyclotron emission (ECE) was proposed and a new, single-sightline ECE system with the heterodyne radiometer has been built for TEXT-U. This ECE system was designed to employ auto- and cross-correlation techniques. Calculations indicate that fluctuations as small as 0.2% in amplitude can be achieved from auto-correlation of the ECE signal. The cross-correlation technique, however, must be used to resolve the fluctuations in frequency. Auto- and cross-correlation between optically thick ECE channels will be used for our initial approach to electron temperature fluctuation measurement with the single-sightline ECE system. A description of the TEXT-U ECE system, investigation of the feasibility of this measurement, and the initial results of test, calibration, and operation are presented.