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Title: Nonrelativistic grey S n -transport radiative-shock solutions

We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that this monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike,more » which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.« less
Authors:
; ;
Publication Date:
Report Number(s):
LA-UR-16-28784
Journal ID: ISSN 1574-1818; TRN: US1700519
Grant/Contract Number:
AC52-06NA25396; AC52-06NA25396 as LA-UR-16-28784
Type:
Accepted Manuscript
Journal Name:
High Energy Density Physics
Additional Journal Information:
Journal Volume: 23; Journal Issue: C; Journal ID: ISSN 1574-1818
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; radiation hydrodynamics; variable Eddington factor; radiative-shock solutions; anti-diffusion
OSTI Identifier:
1345943
Alternate Identifier(s):
OSTI ID: 1397411

Ferguson, J. M., Morel, J. E., and Lowrie, R. B.. Nonrelativistic grey S n -transport radiative-shock solutions. United States: N. p., Web. doi:10.1016/j.hedp.2017.02.010.
Ferguson, J. M., Morel, J. E., & Lowrie, R. B.. Nonrelativistic grey S n -transport radiative-shock solutions. United States. doi:10.1016/j.hedp.2017.02.010.
Ferguson, J. M., Morel, J. E., and Lowrie, R. B.. 2017. "Nonrelativistic grey S n -transport radiative-shock solutions". United States. doi:10.1016/j.hedp.2017.02.010. https://www.osti.gov/servlets/purl/1345943.
@article{osti_1345943,
title = {Nonrelativistic grey S n -transport radiative-shock solutions},
author = {Ferguson, J. M. and Morel, J. E. and Lowrie, R. B.},
abstractNote = {We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that this monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike, which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.},
doi = {10.1016/j.hedp.2017.02.010},
journal = {High Energy Density Physics},
number = C,
volume = 23,
place = {United States},
year = {2017},
month = {6}
}