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Title: Reaction-in-flight neutrons as a test of stopping power in degenerate plasmas

We present the first measurements of reaction-in-flight (RIF) neutrons in an inertial confinement fusion system. The experiments were carried out at the National Ignition Facility, using both Low Foot and High Foot drives and cryogenic plastic capsules. In both cases, the high-energy RIF (E n > 15 MeV) component of the neutron spectrum was found to be about 10 –4 of the total. The majority of the RIF neutrons were produced in the dense cold fuel surrounding the burning hotspot of the capsule, and the data are consistent with a compressed cold fuel that is moderately to strongly coupled (Γ~ 0.6) and electron degenerate (θ Fermie~ 4). The production of RIF neutrons is controlled by the stopping power in the plasma. Thus, the current RIF measurements provide a unique test of stopping power models in an experimentally unexplored plasma regime. In conclusion, we find that the measured RIF data strongly constrain stopping models in warm dense plasma conditions, and some models are ruled out by our analysis of these experiments.
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  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1070-664X; PHPAEN
Grant/Contract Number:
AC52-06NA25396; Not applicable
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 22; Journal Issue: 8; Journal ID: ISSN 1070-664X
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
Country of Publication:
United States
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; neutrons; collisional energy loss; plasma temperature; cryogenics; plasma diagnostics
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1229577