Ion heating and short wavelength fluctuations in a helicon plasma source

Journal Article · Fri Mar 15 04:00:00 EDT 2013 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4794351· OSTI ID:22107654

Scime, E. E.; Carr, J. Jr.; Galante, M.; Magee, R. M. ^[1]; Hardin, R. ^[2]

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1. Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)
2. Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

For typical helicon source parameters, the driving antenna can couple to two plasma modes; the weakly damped 'helicon' wave, and the strongly damped, short wavelength, slow wave. Here, we present direct measurements, obtained with two different techniques, of few hundred kHz, short wavelength fluctuations that are parametrically driven by the primary antenna and localized to the edge of the plasma. The short wavelength fluctuations appear for plasma source parameters such that the driving frequency is approximately equal to the lower hybrid frequency. Measurements of the steady-state ion temperature and fluctuation amplitude radial profiles suggest that the anomalously high ion temperatures observed at the edge of helicon sources result from damping of the short wavelength fluctuations. Additional measurements of the time evolution of the ion temperature and fluctuation profiles in pulsed helicon source plasmas support the same conclusion.

• OSTI ID: 22107654
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 3 Vol. 20; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANTENNAS
APPROXIMATIONS
BOUNDARY LAYERS
FLUCTUATIONS
FREQUENCY MEASUREMENT
ION TEMPERATURE
IONS
KHZ RANGE 100-1000
LOWER HYBRID CURRENT DRIVE
LOWER HYBRID HEATING
PLASMA
RF SYSTEMS
STEADY-STATE CONDITIONS
WAVELENGTHS