Analysis of data from gold spheres imbedded in a gas bag, illuminated by the URLLE Omega laser

ORAL

Abstract

In order to make data from an open Au sphere (previously shot in 2006 and 2013) more ``hohlraum relevant'', we embedded the sphere in a ``gas bag'', comprised of a thin membrane filled with varying amounts of gas. The Thomson Scattering (TS) data from this new campaign gave clear signatures of when the Au expanded out within this surrounding gas to a given radial point at a given time. We analyze this data via radiation-hydrodynamic simulations that include a post-processor that directly mimics the TS spectra vs. time. Within these simulations, we test various non-LTE atomic physics models, as well as electron transport models. One model that appears to fit this new data is a restrictive flux limiter, mimicking the ``Return-Current-Instability''(RCI) which, when operative, is effectively f$=$0.015. The same ion acoustic turbulence (an outgrowth of the RCI), that enhances scattering, and thus inhibits transport, can also increase absorption. This increase in absorption, applied (speculatively) close by the critical surface, is part of the computational model. This same model showed some success with the bare Au sphere data as well, as reported at APS/DPP last year. We also discuss ion diffusion effects.

Authors

  • M. D. Rosen

    LLNL, Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • Steven Ross

    LLNL, Lawrence Livermore National Laboratory, llnl

  • G. Swadling

    Imperial College London, Lawrence Livermore National Laboratory

  • D. E. Hinkel

    LLNL, Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory, Lawrence Livermore National Lab

  • Cliff Thomas

    Lawrence Livermore National Lab, Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • D. A. Callahan

    Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory, LLNL

  • Oggie Jones

    LLNL, Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • G. B. Zimmerman

    LLNL, Lawrence Livermore National Laboratory