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Title: Impact of temperature-velocity distribution on fusion neutron peak shape

Doppler broadening of the 14 MeV DT and 2.45 MeV DD fusion neutron lines has long been our best measure of temperature in a burning plasma. At the National Ignition Facility (NIF), yields are high enough and our neutron spectrometers accurate enough that we see finer details of the peak shape. For example, we can measure the shift of the peak due to the bulk motion of the plasma, and we see indications of non-thermal broadening, skew, and kurtosis of the peak caused by the variations of temperature and fluid velocity during burn. We can also distinguish spectral differences among several lines of sight. Finally, this paper will review the theory of fusion neutron line shape, show examples of non-Gaussian line shapes and directional variations in NIF data, and describe detailed spectral shapes we see in radiation-hydrodynamics simulations of implosions.
Authors:
ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [1] ; ORCiD logo [1] ;  [1] ;  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. General Atomics, San Diego, CA (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-708813
Journal ID: ISSN 1070-664X; TRN: US1700697
Grant/Contract Number:
AC52-07NA27344; NA0001808
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION
OSTI Identifier:
1345328
Alternate Identifier(s):
OSTI ID: 1348022