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Title: Interpreting the electron temperature inferred from x-ray continuum emission for direct-drive inertial confinement fusion implosions on OMEGA

Journal Article · · Physics of Plasmas
DOI: https://doi.org/10.1063/1.5112759 · OSTI ID:1559445

In this paper, we present a theoretical framework for interpreting the hot-spot electron temperature ($$T_e$$) inferred from hard (10- to 20-keV) x-ray continuum emission for inertial confinement fusion implosions on OMEGA. We first show that the inferred $$T_e$$ represents the emission-weighted, harmonic mean of the hot-spot $$T_e$$ distribution, both spatially and temporally. A scheme is then provided for selecting a photon energy of which the emission weighting approximates neutron weighting. Simulations are then used to quantify the predicted relationship between the inferred Te, neutron-weighted Ti, and implosion performance on OMEGA. In an ensemble of 1-D simulations, it was observed that hot-spot thermal nonequilibrium precluded a sufficiently unique mapping between the inferred $$T_e$$ and neutron-weighted Ti. In 3-D simulations with low-harmonic-mode perturbations (i.e., laser beam power imbalance, target offset, and beam port geometry departures from spherical symmetry) and laser imprint (1max = 200).

Research Organization:
Univ. of Rochester, Rochester, NY (United States). Laboratory for Laser Energetics
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
NA0003856
OSTI ID:
1559445
Report Number(s):
2019--43, 1514, 2475; 2019-43, 1514, 2475
Journal Information:
Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 8 Vol. 26; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

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