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Title: Measurement of runaway electron energy distribution function during high-Z gas injection into runaway electron plateaus in DIII-D

The evolution of the runaway electron (RE) energy distribution function f{sub ε} during massive gas injection into centered post-disruption runaway electron plateaus has been reconstructed. Overall, f{sub ε} is found to be much more skewed toward low energy than predicted by avalanche theory. The reconstructions also indicate that the RE pitch angle θ is not uniform, but tends to be large at low energies and small θ ∼ 0.1–0.2 at high energies. Overall power loss from the RE plateau appears to be dominated by collisions with background free and bound electrons, leading to line radiation. However, the drag on the plasma current appears to be dominated by collisions with impurity ions in most cases. Synchrotron emission appears not to be significant for overall RE energy dissipation but may be important for limiting the peak RE energy.
Authors:
; ;  [1] ; ; ;  [2] ; ;  [3] ;  [4] ;  [5]
  1. University of California—San Diego, 9500 Gilman Dr., La Jolla, California 92093 (United States)
  2. General Atomics, PO Box 85608, San Diego, California 92186 (United States)
  3. Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831 (United States)
  4. Institute for Fusion Studies, University of Texas—Austin, 2100 San Jacinto Blvd, Austin, Texas 78712 (United States)
  5. Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
22410388
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 5; Other Information: (c) 2015 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; COLLISIONS; DOUBLET-3 DEVICE; DRAG; ELECTRIC CURRENTS; ENERGY SPECTRA; FUNCTIONS; GAS INJECTION; INCLINATION; IONS; PLASMA IMPURITIES; POWER LOSSES; RUNAWAY ELECTRONS; SYNCHROTRONS