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This content will become publicly available on August 15, 2017

Title: Indications of flow near maximum compression in layered deuterium-tritium implosions at the National Ignition Facility

Here, an accurate understanding of burn dynamics in implosions of cryogenically layered deuterium (D) and tritium (T) filled capsules, obtained partly through precision diagnosis of these experiments, is essential for assessing the impediments to achieving ignition at the National Ignition Facility. We present measurements of neutrons from such implosions. The apparent ion temperatures Tion are inferred from the variance of the primary neutron spectrum. Consistently higher DT than DD Tion are observed and the difference is seen to increase with increasing apparent DT Tion. The line-of-sight rms variations of both DD and DT Tion are small, ~150eV, indicating an isotropic source. The DD neutron yields are consistently high relative to the DT neutron yields given the observed Tion. Spatial and temporal variations of the DT temperature and density, DD-DT differential attenuation in the surrounding DT fuel, and fluid motion variations contribute to a DT Tion greater than the DD Tion, but are in a one-dimensional model insufficient to explain the data. We hypothesize that in a three-dimensional interpretation, these effects combined could explain the results.
Authors:
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  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Univ. of Rochester, Rochester, NY (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. General Atomics, San Diego, CA (United States)
Publication Date:
OSTI Identifier:
1313547
Report Number(s):
LLNL-JRNL--682118
Journal ID: ISSN 2470-0045; PLEEE8
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Physical Review E
Additional Journal Information:
Journal Volume: 94; Journal Issue: 2; Journal ID: ISSN 2470-0045
Publisher:
American Physical Society (APS)
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 29 ENERGY PLANNING, POLICY AND ECONOMY; 70 PLASMA PHYSICS AND FUSION