Title: Detailed high-resolution three-dimensional simulations of OMEGA separated reactants inertial confinement fusion experiments

Abstract

We present results from the comparison of high-resolution three-dimensional (3D) simulations with data from the implosions of inertial confinement fusion capsules with separated reactants performed on the OMEGA laser facility. Each capsule, referred to as a “CD Mixcap,” is filled with tritium and has a polystyrene (CH) shell with a deuterated polystyrene (CD) layer whose burial depth is varied. In these implosions, fusion reactions between deuterium and tritium ions can occur only in the presence of atomic mix between the gas fill and shell material. The simulations feature accurate models for all known experimental asymmetries and do not employ any adjustable parameters to improve agreement with experimental data. Simulations are performed with the RAGE radiation-hydrodynamics code using an Implicit Large Eddy Simulation (ILES) strategy for the hydrodynamics. We obtain good agreement with the experimental data, including the DT/TT neutron yield ratios used to diagnose mix, for all burial depths of the deuterated shell layer. Additionally, simulations demonstrate good agreement with converged simulations employing explicit models for plasma diffusion and viscosity, suggesting that the implicit sub-grid model used in ILES is sufficient to model these processes in these experiments. In our simulations, mixing is driven by short-wavelength asymmetries and longer-wavelength featuresmore » are responsible for developing flows that transport mixed material towards the center of the hot spot. Mix material transported by this process is responsible for most of the mix (DT) yield even for the capsule with a CD layer adjacent to the tritium fuel. Consistent with our previous results, mix does not play a significant role in TT neutron yield degradation; instead, this is dominated by the displacement of fuel from the center of the implosion due to the development of turbulent instabilities seeded by long-wavelength asymmetries. Through these processes, the long-wavelength asymmetries degrade TT yield more than the DT yield and thus bring DT/TT neutron yield ratios into agreement with experiment. Finally, we present a detailed comparison of the flows in 2D and 3D simulations.« less

Authors:

Haines, Brian Michael ^[1]; Grim, Gary P. ^[2]; Fincke, James R. ^[1]; Shah, Rahul C. ^[1]; Forrest, Chad J. ^[3]; Silverstein, Kevin ^[3]; Marshall, Frederic J. ^[3]; Boswell, Melissa  ^[1];

• Search DOE PAGES for author "Boswell, Melissa"
• Search DOE PAGES for ORCID "0000-0001-6945-640X"

Fowler, Malcolm M. ^[1]; Gore, Robert A. ^[1]; Hayes-Sterbenz, Anna Catherine ^[1]; Jungman, Gerard ^[1]; Klein, Andreas  ^[1];

• Search DOE PAGES for author "Klein, Andreas"
• Search DOE PAGES for ORCID "0000-0003-2358-2691"

Rundberg, Robert S.  ^[1];

• Search DOE PAGES for author "Rundberg, Robert S."
• Search DOE PAGES for ORCID "0000-0003-2652-0090"

Steinkamp, Michael James ^[1]; Wilhelmy, Jerry B.  ^[1]

• Search DOE PAGES for author "Wilhelmy, Jerry B."
• Search DOE PAGES for ORCID "0000-0002-0406-4904"

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
3. Univ. of Rochester, Rochester, NY (United States)

Publication Date:

Fri Jul 29 00:00:00 EDT 2016

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1329906

Alternate Identifier(s):

OSTI ID: 1275974; OSTI ID: 1366906

Report Number(s):

LA-UR-16-24138; LLNL-JRNL-709437
Journal ID: ISSN 1070-664X; PHPAEN

Grant/Contract Number:  

AC52-06NA25396; AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 23; Journal Issue: 7; Journal ID: ISSN 1070-664X

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; neutrons; surface measurements; hydrodynamics; diffusive energy transport; experiment design