Resonance Cone Interaction With a Self-Consistent Radio-Frequency Sheath

Journal Article · Fri Nov 07 04:00:00 EST 2008 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.101.195004· OSTI ID:21179897

Myra, J R; D'Ippolito, D A ^[1]

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1. Lodestar Research Corporation, 2400 Central Avenue P-5, Boulder, Colorado 80301 (United States)

We study the propagation of lower-hybrid-type resonance cones in a tenuous magnetized plasma, and, in particular, their interaction with, and reflection from, the plasma sheath near a conducting wall. The sheath is modeled as a vacuum gap whose width is given by the Child-Langmuir law. The application of interest is when the resonance cones are launched (parasitically) by an ion-cyclotron radio-frequency antenna in a typical rf-heated tokamak fusion experiment. We calculate the fraction of launched voltage in the resonance cones that is transmitted to the sheath, and show that it has a sensitive thresholdlike turn on when a critical parameter reaches order unity. Above threshold, the fractional voltage transmitted to the sheath is order unity, leading to strong and potentially deleterious rf-wall interactions in tokamak rf heating experiments. Below threshold, these interactions can be avoided.

• OSTI ID: 21179897
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 19 Vol. 101; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANTENNAS
CONES
CYCLOTRONS
ELECTRIC POTENTIAL
INTERACTIONS
LOWER HYBRID HEATING
PLASMA
PLASMA SHEATH
RADIOWAVE RADIATION
RESONANCE
TOKAMAK DEVICES