Lower Hybrid Experiments on PLT Using Grills Having Various n/sub Parallel/ Spectral Widths

摘要

Coupling structures for lower hybrid current drive experiments have, until now, been smaller than a free space wavelength and have had a correspondingly broad wave number spectrum. In this paper we report the results of experiments on the PLT tokamak using a 16-waveguide grill (2.2 wavelengths) which produces a very narrow n/sub parallel/ = k/sub parallel/c/ omega spectrum. Experimental results from the 16-waveguide grill are compared with results from three other PLT grills with less sharply defined n/sub parallel/ spectra. The current drive figure of merit, I/sub p/n/sub e/R/P/sub rf/ approx. =0.14 x 10 sup 14 A cm sup -3 m/W, is approx. =40% higher for the 16-waveguide coupler than for previously reported experiments on PLT, in spite of the larger ''spectral gap.'' 60 refs. (ERA citation 12:044736)