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Abstract

28 GHz 2W-ce ECRH has been applied to CLEO stellarator, using a low current ohmically heated target plasma with n-e approximately equal 3 x 10RU1RU2/cc. The high efficiency absorption of the X-mode at 2W-ce is seen to fall rapidly when n-e rises through approximately equal 0.9 n-crit. During the ECRH pulse at high power the plasma density only falls for a few ms, then rises, quickly reaching the n-c value of 5 x 10**12/cc at which loop voltage and diamagnetic evidence shows a loss of heating. This density rise limits the power and/or duration of the RF pulse, to eg 120 kW, 25 ms. Diamagnetically determined stored energy has no density dependence below 0.9 n-c, no strong variation with TOT and no apparent sensitivity to plasma current <or= 5 kA. Another parameter varied: the vertical field had a small effect on the density rise but no significant effect on <beta>. Evidence exists of 3 helical tracks of X-ray emission from the torus wall a broad hot central plasma. Free boundary equilibria calculated for representative CLEO parameters show a substantial magnetic axis shift. Attempts to raise the toroidal field produced severe hard X-ray fluxes and reduced diamagnetism. Future plans for CLEO stellarator include improved antenna structures, operation at 60 GHz, 200 kW and various types of helically assisted tokamaks.

Additional information

Authors: TODD T N, UKAEA CULHAM LABORATORY, ABINGDON (UK);TAKAMURA S, UKAEA CULHAM LABORATORY, ABINGDON (UK);HENDER T, UKAEA CULHAM LABORATORY, ABINGDON (UK);CLEO TEAM UKAEA CULHAM LABORATORY, ABINGDON (UK), UKAEA CULHAM LABORATORY, ABINGDON (UK)
Bibliographic Reference: 5TH INTERNATIONAL WORKSHOP ON STELLARATORS, SCHLOSS RINGBERG, BAVARIA (GERMANY) SEPT. 24-28, 1984 VOL. I, PP. 173-178, EUR 9618 EN (1985) FS, VOL. I AND VOL. II, 787 P., BFR 3500 (BOTH VOLUMES), EUROFFICE, LUXEMBOURG, POB 1003
Record Number: 1989124118800 / Last updated on: 1987-01-01
Category: PUBLICATION
Available languages: en
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