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Diagnostic signatures of performance degrading perturbations in inertial confinement fusion implosions

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Title: Diagnostic signatures of performance degrading perturbations in inertial confinement fusion implosions
Authors: McGlinchey, K
Appelbe, BD
Crilly, AJ
Tong, JK
Walsh, CA
Chittenden, JP
Item Type: Journal Article
Abstract: We present 3D radiation-hydrodynamics simulations of indirect-drive inertial confinement fusion experiments performed at the National Ignition Facility (NIF). The simulations are carried out on two shots from different NIF experimental campaigns: N130927 from the high foot series and N161023 from the ongoing high density carbon series. Applying representative perturbation sources from each implosion, synthetic nuclear diagnostics are used to post-process the simulations to infer the stagnation parameters. The underlying physical mechanisms that produce the observed signatures are then explored. We find that the radiation asymmetry and tent scar perturbations extend the nuclear burn width; this is due to an asymmetric stagnation of the shell that causes the delivery of mechanical PdV work to be extended compared to an idealised implosion. Radiation asymmetries seed directed flow patterns that can result in a difference in the inferred ion temperature ranging from 80 eV to 230 eV depending on the magnitude and orientation of the asymmetry considered in the simulation; the tent scar shows no such temperature difference. For N130927, radiation asymmetries dominate the yield and inferred ion temperature and the tent scar has the largest influence on the neutron burnwidth. For N161023, the fill tube decreases the burn width by injecting mix into the hot spot, leading to a smaller hot spot and increased energy losses. Both the radiation asymmetry and the fill tube generate directed flows that lead to an anisotropic inferred temperature distribution. Through existing and novel synthetic neutron imaging techniques, we can observe the hot spot and shell shape to a degree that accurately captures the perturbations present.
Issue Date: 1-Dec-2018
Date of Acceptance: 30-Nov-2018
URI: http://hdl.handle.net/10044/1/65678
DOI: https://dx.doi.org/10.1063/1.5064504
ISSN: 1070-664X
Publisher: AIP Publishing
Journal / Book Title: Physics of Plasmas
Volume: 25
Issue: 12
Copyright Statement: © 2018 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas 2018 25:12 and may be found at https://dx.doi.org/10.1063/1.5064504
Sponsor/Funder: AWE Plc
Engineering & Physical Science Research Council (E
Engineering & Physical Science Research Council (EPSRC)
Lawrence Livermore National Laboratory
Funder's Grant Number: 300115146/1
Keywords: 0202 Atomic, Molecular, Nuclear, Particle And Plasma Physics
0201 Astronomical And Space Sciences
0203 Classical Physics
Fluids & Plasmas
Publication Status: Published
Online Publication Date: 2018-12-18
Appears in Collections:Physics
Plasma Physics
Faculty of Natural Sciences