STUDIES OF EDGE PHENOMENA IN JET WITH VISIBLE SPECTROSCOPY
Visible spectroscopy affords an effective means of studying edge phenomena in JET, by monitoring the behaviour of lowly ionized or neutral states. Here we report on the following edge related topics. (a) effect of RF heating on minority species; (b) MARFES, and (c) Zeeman splitting of impurity lines. Light from a tangential chord viewing a carbon limiter is coupled by 120 metres of high transmission 1 mm quartz fibre to a Czerny-Turner spectrometer. A calibrated Optical Multichannel Analyser (OMA) samples 16 nm increments of the output spectrum with a resolution of 0.03 nm and a variable time resolution (set to 196 ms). The available spectral range has been surveyed and the main impurities identified. Impurity atoms and ions of the usual impurities such as O, C, Cr with multiplets conveniently close to the Balmer Series are routinely monitored. The survey aspect of the diagnostic is particularly valuable however in detecting unexpected elements or unforeseen plasma or impurity behaviour.
Bibliographic Reference: 12TH EUROPEAN CONFERENCE ON CONTROLLED FUSION AND PLASMA PHYSICS, BUDAPEST (HUNGARY), SEPT. 2-6, 1985 PP. 109-112 WRITE TO THE PUBLICATIONS OFFICER, JET JOINT UNDERTAKING, ABINGDON, OXON, OX14 3EA (UK), MENTIONING REPORT JET-P(85)10, 1985
Record Number: 1989124056900 / Last updated on: 1987-01-01
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