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National Ignition Facility Polar-Drive Exploding-Pusher Experiments Improving Performance via Imprint Mitigation

ORAL

Abstract

Exploding pushers (XP’s) produced the highest polar-direct-drive (PDD) DT yield (~1.1x1016) on the National Ignition Facility (NIF) using a ~1.1-MJ pulse illuminating a ~4-mm-diam, 25-mm CH target. Development continues to improve DT yield with an ultimate goal >2x1016. These NIF PDD-XP targets provide a high-yield neutron source as well as a platform to develop predictive inertial confinement fusion modeling using the 2-D code DRACO. Recent NIF PDD-XP experiments focused on a smaller 3.4-mm-diam target using a DD fill as a surrogate target to keep the illumination intensity similar to the 4-mm-diam targets while increasing shot throughput with its modest facility impact. Shell morphology was improved as predicted by DRACO but the yield was not affected unless the deleterious imprint was included. In addition, the NIF PDD-XP experiments across the larger target diameters (>3 mm) with either DT or DD fills have indicated sensitivity to imprint. Potential yield degradation sources guided the design of subsequent experiments at 3.4-mm scale to assess the impact of imprint mitigation via pulse-shape control as one method to improve performance while improving predictive code capability. The 3.4-mm-scale target results are presented here.

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Presenters

  • John A Marozas

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

Authors

  • John A Marozas

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

  • Michael J Rosenberg

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

  • Patrick m McKenty

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

  • Timothy J Collins

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

  • Valeri N Goncharov

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

  • Sean P Regan

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

  • Mike M Campbell

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

  • Laurent Divol

    Lawrence Livermore Natl Lab

  • Gregory E Kemp

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

  • Charles B Yeamans

    Lawrence Livermore Natl Lab, LLNL, Lawrence Livermore National Lab, Lawrence Livermore Natl. Lab