Absorption of Fast Waves at Moderate to High Ion Cyclotron Harmonics on DIII-D

Journal Article · Mon Sep 26 04:00:00 EDT 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2098199· OSTI ID:20726371

Pinsker, R I; Petty, C C; Prater, R; Choi, M ^[1]; Porkolab, M ^[2]; Heidbrink, W W; Luo, Y ^[3]; Baity, F W; Murakami, M ^[4]; Fredd, E; Hosea, J C ^[5]; Harvey, R W; Smirnov, A P ^[6]; Van Zeeland, M A ^[7]

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1. General Atomics, P.O. Box 85608, San Diego, California, 92186-5608 (United States)
2. Massachusetts Institute of Technology, Cambridge, Massachusetts (United States)
3. University of California, Irvine, California (United States)
4. Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States)
5. Princeton Plasma Physics Laboratory, Princeton, New Jersey (United States)
6. CompX, Del Mar, California (United States)
7. Oak Ridge Institute for Science Education, Oak Ridge, Tennessee (United States)

The absorption of fast Alfven waves (FW) by ion cyclotron harmonic damping in the range of harmonics from fourth to eighth is studied theoretically and with experiments in the DIII-D tokamak. A formula for linear ion cyclotron absorption on Maxwellian ion species is used to estimate the single-pass damping for various cases of experimental interest. It is found that damping on fast ions from neutral beam injection can be significant even at the eighth harmonic if the fast ion beta and the background plasma density are both high enough. The predictions are tested in several L-mode experiments in DIII-D with FW power at 60 MHz and at 116 MHz. It is found that 4th and 5th harmonic absorption of the 60 MHz power on the beam ions can be quite strong, but 8th harmonic absorption of the 116 MHz power appears to be weaker than expected. Possible explanations of the discrepancy are discussed.

• OSTI ID: 20726371
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 787; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABSORPTION
ALFVEN WAVES
BEAM INJECTION HEATING
CYCLOTRON HARMONICS
DAMPING
DOUBLET-3 DEVICE
ELECTROMAGNETIC RADIATION
IONS
L-MODE PLASMA CONFINEMENT
MHZ RANGE
NEUTRAL ATOM BEAM INJECTION
PLASMA
PLASMA DENSITY