Observation of Non-Maxwellian Electron Distributions in th e NSTX Divertor
Authors: M.A. Jaworski, et. al.
Abstract:
The scrape-off layer plasma at the tokamak region is characterized by open field lines and often
contains large variations in plasma properties along these field-lines. Proper characterization of
local plasma conditions is critical to assessing plasma-material interaction processes occuring
at the target. Langmuir probes are frequently employed in tokamak divertors but are challenging
to interpretation. A kinetic interpretation for Langmuir probes in NSTX has yielded
non-Maxwellian electron distributions in the divertor characterized by cool bulk populations
and energetic tail populations with temperatures of 2-4 times the bulk. Spectroscopic analysis
and modeling confirms the bulk plasma temperature and density which can only be obtained
with the kinetic interpretation
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Submitted to: Journal of Nuclear Materials, (June 2012) and 20th Plasma-Surface Intractions Conference, Aachen, Germany, (May 2012)
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Download PPPL-4854 (pdf 464 KB 18 pp)
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