The effect of ICRF on the Alcator C Scrape-Off Layer plasma
This paper presents a characterization of the Alcator C Scrape-Off Layer (SOL) plasma during ICRF hydrogen-minority fast wave heating experiments. The SOL plasma parameters were measured using a multifunctional probe, JANUS, which is capable of simultaneously measuring the ion and electron parameters both parallel and antiparallel with respect to the toroidal magnetic field. The probe data indicate, at low value of injected rf power, there is direct edge heating and density increases at radii greater than that of the antenna Faraday shield. Increasing the injected rf power spreads both the temperature and density increases throughout the edge region, flattening the radial profiles. Varying the position of the resonance layer in the main plasma does not significantly change the effect of ICRF on the SOL parameters. Given this single spatial point characterization of the SOL, a crude estimate of power flow into and through the edge plasma indicate that /approximately/20% of the ICRF power launched from the antenna is absorbed /und directly/ in the SOL plasma. Additional observation of the impurity source rates confirms the conclusions of an earlier paper, which attributed increasing central densities of high-Z impurities to the increase in physical sputtering rate at both the ICRF antenna's Faraday shield and the limiter surface.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48; AC02-78ET51013
- OSTI ID:
- 5041415
- Report Number(s):
- UCRL-98600; CONF-880512-1; CONF-880512-; ON: DE88009821
- Resource Relation:
- Conference: 8. international conference on plasma surface interactions in controlled fusion devices, Julich, F.R. Germany, 2 May 1988
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALCATOR DEVICE
PLASMA SCRAPE-OFF LAYER
PLASMA HEATING
ANTENNAS
INERTIAL CONFINEMENT
BOUNDARY LAYERS
CLOSED PLASMA DEVICES
CONFINEMENT
ELECTRICAL EQUIPMENT
EQUIPMENT
HEATING
LAYERS
PLASMA CONFINEMENT
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
700208* - Fusion Power Plant Technology- Inertial Confinement Technology