부산대학교 도서관

A fast-scanning heterodyne radiometer employing a backward-wave oscillator (BWO) in 78-118 GHz was developed and installed for electron cyclotron emission (ECE) measurements in HT-7 superconducting tokamak. The radiometer measures 16 ECE frequency points with a scanning time period of 0.65 ms, each of the frequency points can be preset by the program to meet specific interests in physics. The high scanning speed is achieved by carefully choosing a BWO, very finely adjusting the radiometer over the full waveband, and by eliminating some elements that are routinely included in a fast-scanning radiometer system. A horizontal view of the ECE optics was installed to measure electron temperature profiles. The spatial resolution is about 1 cm (B[sub t]=2 T) in the center of the HT-7 minor cross section, determined by the intermediate frequency of 0.1-0.5 GHz in the radiometer. Vertically viewing optics along a perpendicular chord was also installed to study nonthermal ECE spectra. Preliminary measurement results in pellet injection plasma and lower-hybrid current drive plasma were presented. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]