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Title: Direct extraction of coherent mode properties from imaging measurements in a linear plasma column

Spectral properties of coherent waves in an argon plasma column are examined using fluctuation data from fast imaging. Visible light from ArII line emission is collected at high frame rates using a high-speed digital camera. A cross-spectral phase technique allows direct visualization of dominant phase structures as a function of frequency, as well as identification of azimuthal asymmetries present in the system. Experimental dispersion estimates are constructed from imaging data alone. Drift-like waves are identified by comparison with theoretical dispersion curves, and a tentative match of a low-frequency spectral feature to Kelvin-Helmholtz-driven waves is presented. Imaging measurements are consistent with previous results, and provide non-invasive, single-shot measurements across the entire plasma cross-section. Implications of the measured spectral properties for imaging measurements of mode dynamics are explored.
Authors:
; ;  [1] ;  [2] ; ; ;  [1] ;  [2]
  1. Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22227874
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 8; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ARGON; CAMERAS; COMPARATIVE EVALUATIONS; FLUCTUATIONS; FREQUENCY DEPENDENCE; HELMHOLTZ INSTABILITY; IMAGES; PLASMA; PLASMA DIAGNOSTICS; PLASMA DRIFT; PLASMA WAVES; VISIBLE RADIATION