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Title: Three-dimensional simulations of National Ignition Facility implosions: Insight into experimental observables

We simulate in 3D both the hydrodynamics and, simultaneously, the X-ray and neutron diagnostic signatures of National Ignition Facility (NIF) implosions. We apply asymmetric radiation drive to study the impact of low mode asymmetry on diagnostic observables. We examine X-ray and neutron images as well as neutron spectra for these perturbed implosions. The X-ray images show hot spot evolution on small length scales and short time scales, reflecting the incomplete stagnation seen in the simulation. The neutron images show surprising differences from the X-ray images. The neutron spectra provide additional measures of implosion asymmetry. Flow in the hot spot alters the neutron spectral peak, namely, the peak location and width. The changes in the width lead to a variation in the apparent temperature with viewing angle that signals underlying hot spot asymmetry. We compare our new expectations based on the simulated data with NIF data. We find that some recent cryogenic layered experiments show appreciable temperature anisotropy indicating residual flow in the hot spot. We also find some trends in the data that do not reflect our simulation and theoretical understanding.
Authors:
; ; ; ; ; ; ; ;  [1] ;  [2] ; ;  [3]
  1. Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States)
  2. Laboratory for Laser Energetics, 250 E. River Road, Rochester, New York 14623-1212 (United States)
  3. General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)
Publication Date:
OSTI Identifier:
22410413
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; ANISOTROPY; ASYMMETRY; COMPUTERIZED SIMULATION; EXPERIMENTAL DATA; HOT SPOTS; HYDRODYNAMICS; IMAGES; IMPLOSIONS; NEUTRON SPECTRA; STAGNATION; THREE-DIMENSIONAL CALCULATIONS; US NATIONAL IGNITION FACILITY; X-RAY RADIOGRAPHY