STUDIES OF THE EDGE PLASMA IN JET BY VISIBLE SPECTROSCOPY DURING ICRF HEATING
RF heating power on JET is coupled to the D**.f5<&< plasma by minority heating of He**-3 or H. Extensive line shape studies have been made of the HeII 468.5 nm line before and during RF heating pulses. Significant changes in the HeII line shape have been observed. We have found it possible to represent the line shape in terms of a simple model for a wide range of launched RF power. The analysis is based on a two Gaussian best fit to the observed spectrum after deconvolution of the instrumental function. This simple model gives an excellent fit to the experimental data and results in a narrow Gaussian corresponding to 80-100 eV temperature and a hotter component of 200-300 eV. The cold "zone" remains unchanged throughout the heating pulse of 30-40% for some antennae. This is accompanied by large changes in the ratios of the areas of the Gaussians. The variation of the line broadening with antenna configuration is evaluated.
Bibliographic Reference: 27TH ANNUAL MEETING OF THE DIVISION OF PLASMA PHYSICS, SAN DIEGO (USA), NOV. 4-8, 1985 PAPER 3P5, PROCEEDINGS P. 1415
Record Number: 1989124128400 / Last updated on: 1987-01-01
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