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Impact of mid-Z gas fill on dynamics and performance of shock-driven implosions at the OMEGA laser

ORAL

Abstract

Shock-driven implosions with 100% D2 gas-fill compared to implosions with 50:50 N2D2 gas-fill have been performed at the OMEGA laser facility to test the impact of the added mid-Z fill gas on implosion dynamics and performance. Ion temperature (Tion) as inferred from the width of measured DD-neutron spectra from experiments with 7um-thick (8-um thick) CH shells is seen to be 34±6% (8±2%) higher for the N2D2 implosions than for the D2-only case, while the DD-neutron yield from the D2-only implosion is 7.2±0.5 (5.5±0.3) times higher than from the N2D2 gas-fill. In this talk, the implications of these results in terms of shock heating scaling with mass, interspecies equilibration rates, radiative loss, and diffusive shell mixing are discussed. The Tion enhancement is found to result from more efficient shock coupling to N than to D, heat transfer from N to D on the time scale of the implosion, and insufficient ion-electron equilibration for radiative loss to propagate to the ions before burn. The yield difference results from a lower fraction of the D content being hot enough to burn in the N2D2-fill than in the D2-only fill implosions.

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Presenters

  • Maria Gatu-Johnson

    MIT, Massachusetts Institute of Technology MI, Massachusetts Institute of Technology

Authors

  • Maria Gatu-Johnson

    MIT, Massachusetts Institute of Technology MI, Massachusetts Institute of Technology

  • Patrick J Adrian

    Massachusetts Institute of Technology (MIT), MIT, Massachusetts Institute of Technology

  • Justin H Kunimune

    Massachusetts Institute of Technology MI, PSFC, MIT, MIT

  • Chikang Li

    Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology

  • Richard D Petrasso

    Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology

  • Fredrick H Seguin

    Massachusetts Institute of Technology MIT

  • Graeme D Sutcliffe

    Massachusetts Institute of Technology

  • Johan A Frenje

    Massachusetts Institute of Technology MIT, PSFC, MIT, MIT, Massachusetts Institute of Technology

  • Chad J Forrest

    Laboratory for Laser Energetics, Laboratory for Laser Energetics, University of Rochester, University of Rochester, Laboratory for Laser Energetics at the University of Rochester, Laboratory for Laser Energetics, U. of Rochester

  • Vladimir Y Glebov

    Lab for Laser Energetics, University of Rochester, Laboratory for Laser Energetics, University of Rochester

  • Neel V Kabadi

    University of Rochester, LLE, MIT, Laboratory of Laser Energetics

  • Christian Stoeckl

    University of Rochester, Laboratory for Laser Energetics, U. of Rochester, Laboratory for Laser Energetics, University of Rochester

  • Hong W Sio

    Lawrence Livermore Natl Lab

  • Lauren Green

    Los Alamos National Laboratory

  • Brian M Haines

    Los Alamos National Laboratory, Los Alamos National Lab

  • Brett Keenan

    Los Alamos Natl Lab

  • William T Taitano

    Los Alamos National Laboratory

  • Brian D Appelbe

    Imperial College London, Imperial College

  • Aidan C Crilly

    Imperial College London, Imperial College

  • Grigory Kagan

    Imperial College, Imperial College London