Experimental investigation of the source of mode one asymmetries in indirect-drive ICF implosions

ORAL

Abstract

While recent indirect-drive ICF implosions on the NIF have demonstrated record performance such as a yield amplification of 3 and hot spot pressures of ~360 Gbar1, 3D asymmetry of the hot spot and assembled cold fuel shell continues to be a key performance degradation mechanism. In particular, measurements of the bulk hot-spot velocity from neutron time-of-flight measurements and spatial variations in the shell areal density from neutron activation diagnostics indicate a systematic mode-1 asymmetry. Diagnostic windows are cut out of the high-Z gold or depleted uranium hohlraum in order to provide a diagnostic line-of-sight for hot spot self-emission x-rays and to allow imaging of the capsule fuel pre-shot. One hypothesis for the low-mode asymmetry is that these windows are reducing the x-ray drive in the window directions. We will report on a series of experiments systematically varying the size of the hohlraum windows and the effect on implosion shape, hot-spot velocity, rhoR variations, and overall performance.

1S. Le Pape, et al., Phys. Rev. Lett. 120, 245003 (2018)

*This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, Lawrence Livermore National Security, LLC. LLNL-ABS-753586.

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Presenters

  • Tammy Yee Wing Ma

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

Authors

  • Tammy Yee Wing Ma

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • Derek A. Mariscal

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Lab

  • Pravesh K Patel

    • Lawrence Livermore Natl Lab

  • Sebastien Le Pape

    • Lawrence Livermore Natl Lab

  • Laura F. Berzak Hopkins

    • Lawrence Livermore Natl Lab

  • Arthur E. Pak

    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Laboratory

  • Laura Robin Benedetti

    • Lawrence Livermore Natl Lab

  • Benjamin Bachmann

    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Lab

  • Paul T Springer

    • Lawrence Livermore Natl Lab

  • Chris V Young

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • Ryan Nora

    • Lawrence Livermore Natl Lab

  • Jayson Dean Lucius Peterson

    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Laboratory

  • Omar A Hurricane

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • Debra Ann Callahan

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab
    • LLNL