Characterisation of SOL density fluctuations in front of the LHCD PAM launcher in Tore

Journal Article · Fri Dec 23 00:00:00 EST 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3664969· OSTI ID:21612484

Oosako, T; Ekedahl, A; Goniche, M; Achard, J; Decker, J; Peysson, Y ^[1]

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1. CEA, IRFM, F-13108 Saint Paul-lez-Durance (France)

The density fluctuations, modified by Lower Hybrid Wave (LHW), is analyzed in Tore Supra with reference to the injected LHW power, density and the gap between LCFS (Last Closed Flux Surface) and the PAM (passive-active-multijunction) launcher. The density fluctuations are measured with RF probes installed at the PAM launcher front. A density scan at nominal toroidal field (3.8 T) shows that the fluctuations rate stays nearly constant ({approx}50%) for <n{sub e}><3.5x10{sup 19}m{sup -3} and with LHW power up to 2MW. However, when increasing the density above <n{sub e}><{approx}4.2x10{sup 19}m{sup -3}, using strong gas puffing, the fluctuation rate increases to >70% and is characterized by strong negative spikes, with typical frequency >100kHz. These are most likely originating from acceleration of electrons in the LHW near field due to parasitic absorption, as evidenced on the IR images, showing hot spots on the side limiters.

• OSTI ID: 21612484
• Journal Information: AIP Conference Proceedings, Vol. 1406, Issue 1; Conference: 9. topical conference on radio frequency power in plasmas, Newport (United States), 1-3 Jun 2011; Other Information: DOI: 10.1063/1.3664969; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABSORPTION
ANTENNAS
DATA ACQUISITION
ELECTRONS
FLUCTUATIONS
HOT SPOTS
LIMITERS
LOWER HYBRID CURRENT DRIVE
LOWER HYBRID HEATING
MAGNETIC SURFACES
PLASMA
PLASMA DENSITY
PLASMA SCRAPE-OFF LAYER
POWER DENSITY
TORE SUPRA TOKAMAK
WAVE PROPAGATION
BOUNDARY LAYERS
CLOSED PLASMA DEVICES
ELECTRICAL EQUIPMENT
ELEMENTARY PARTICLES
EQUIPMENT
FERMIONS
HEATING
HIGH-FREQUENCY HEATING
LAYERS
LEPTONS
MAGNETIC FIELD CONFIGURATIONS
NON-INDUCTIVE CURRENT DRIVE
PLASMA HEATING
SORPTION
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
VARIATIONS