skip to main content

SciTech ConnectSciTech Connect

Title: Alfvénic oscillations of the electron distribution function: Linear theory and experimental measurements

Wave propagation can be an accurate method for determining material properties. High frequency whistler mode waves (0.7 < ω/|Ω{sub ce}| < 1) in an overdense plasma (ω{sub pe} > |Ω{sub ce}|) are damped primarily by Doppler-shifted electron cyclotron resonance. A kinetic description of whistler mode propagation parallel to the background magnetic field shows that damping is proportional to the parallel electron distribution function. This property enables an experimental determination of the parallel electron distribution function using a measurement of whistler mode wave absorption. The whistler mode wave absorption diagnostic uses this technique on UCLA’s Large Plasma Device (LaPD) to measure the distribution of high energy electrons (5 − 10v{sub te}) with 0.1% precision. The accuracy is limited by systematic effects that need to be considered carefully. Ongoing research uses this diagnostic to investigate the effect of inertial Alfvén waves on the electron distribution function. Results presented here verify experimentally the linear effects of inertial Alfvén waves on the reduced electron distribution function, a necessary step before nonlinear physics can be tested. Ongoing experiments with the whistler mode wave absorption diagnostic are making progress toward the first direct detection of electrons nonlinearly accelerated by inertial Alfvén waves, a process believed tomore » play an important role in auroral generation.« less
Authors:
; ; ;  [1] ; ;  [2]
  1. Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)
  2. Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)
Publication Date:
OSTI Identifier:
22496180
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1689; Journal Issue: 1; Conference: 21. topical conference on radio frequency power in plasmas, Lake Arrowhead, CA (United States), 27-29 Apr 2015; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; ACCURACY; ALFVEN WAVES; DIAGNOSTIC USES; DISTRIBUTION FUNCTIONS; DOPPLER EFFECT; ELECTRON CYCLOTRON-RESONANCE; ELECTRONS; MAGNETIC FIELDS; NONLINEAR PROBLEMS; OSCILLATIONS; PLASMA; WAVE PROPAGATION; WHISTLER INSTABILITY