Measurements of parallel electron velocity distributions using whistler wave absorption

Journal Article · Wed Aug 15 00:00:00 EDT 2012 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4742766· OSTI ID:22093700

Thuecks, D. J.; Skiff, F.; Kletzing, C. A. ^[1]

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1. Department of Physics and Astronomy, University of Iowa, 203 Van Allen Hall, Iowa City, Iowa 52242 (United States)

We describe a diagnostic to measure the parallel electron velocity distribution in a magnetized plasma that is overdense ({omega}{sub pe} > {omega}{sub ce}). This technique utilizes resonant absorption of whistler waves by electrons with velocities parallel to a background magnetic field. The whistler waves were launched and received by a pair of dipole antennas immersed in a cylindrical discharge plasma at two positions along an axial background magnetic field. The whistler wave frequency was swept from somewhat below and up to the electron cyclotron frequency {omega}{sub ce}. As the frequency was swept, the wave was resonantly absorbed by the part of the electron phase space density which was Doppler shifted into resonance according to the relation {omega}-k{sub ||v||} = {omega}{sub ce}. The measured absorption is directly related to the reduced parallel electron distribution function integrated along the wave trajectory. The background theory and initial results from this diagnostic are presented here. Though this diagnostic is best suited to detect tail populations of the parallel electron distribution function, these first results show that this diagnostic is also rather successful in measuring the bulk plasma density and temperature both during the plasma discharge and into the afterglow.

• OSTI ID: 22093700
• Journal Information: Review of Scientific Instruments, Vol. 83, Issue 8; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ABSORPTION
AFTERGLOW
CYCLOTRON FREQUENCY
DIPOLES
DISTRIBUTION
DISTRIBUTION FUNCTIONS
DOPPLER EFFECT
ELECTRON TEMPERATURE
ELECTRONS
ION TEMPERATURE
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
PHASE SPACE
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
RESONANCE
VELOCITY
WHISTLERS