Laser–Plasma Interaction Experiments at Direct-Drive Ignition-Relevant Scale Lengths at the National Ignition Facility

ORAL

Abstract

Experiments at the National Ignition Facility have probed laser-plasma interactions and hot-electron production at plasma conditions relevant to direct-drive ignition, with predicted density scale lengths of Ln ~500-700 μm, electron temperatures of Te ~4-5 keV, and overlapped laser intensities of I ~6-15 × 1014 W/cm2. The fraction of laser energy converted to hot electrons is 1-3%, while the hot-electron temperature is 45-60 keV. Only a sharp red-shifted feature is observed around ω/2, along with significant stimulated Raman scattering (SRS), including sidescattering, at lower densities, suggesting that SRS dominates hot-electron production, unlike in shorter-scale-length plasmas on OMEGA that are dominated by two-plasmon decay (TPD). This difference in regime is explained based on absolute SRS and TPD threshold considerations. Subsequent measurements of 3ω/2 emission have revealed evidence of TPD; upcoming experiments will identify dominant plasma waves. The coupling of hot electrons to an implosion will be measured in new experiments, which will determine the need for preheat mitigation strategies for direct-drive ignition.

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Presenters

  • Michael J Rosenberg

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

Authors

  • Michael J Rosenberg

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

  • Andrey Solodov

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

  • Russell Follett

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

  • Wolf Seka

    Laboratory for Laser Energetics, University of Rochester

  • Sean P Regan

    Univ of Rochester, Univ of Rochester, Univ of Rochester, Laboratory for Laser Energetics, Laboratory for Laser Energetics, University of Rochester, Laboratory for Laser Energetics U. of Rochester, Laboratory for Laser Energetics, U. of Rochester, Laboratory for Laser Energetics, Rochester, New York, University of Rochester, Lab for Laser Energetics

  • Reuben Epstein

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

  • Alison R Christopherson

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

  • Riccardo Betti

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

  • A. V. Maximov

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

  • Timothy J Collins

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

  • Valeri N Goncharov

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

  • Robert W Short

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

  • David Turnbull

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

  • Dustin H Froula

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

  • Radha Bahukutumbi

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

  • Jason F Myatt

    University of Alberta, Univ of Alberta

  • Pierre A Michel

    Lawrence Livermore Natl Lab, LLNL, Lawrence Livermore National Laboratory

  • Matthias Hohenberger

    Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory

  • Laurent Pierre Masse

    Lawrence Livermore National Laboratory, LLNL, Livermore, CA 94550, USA, Lawrence Livermore Natl Lab

  • George F Swadling

    Imperial College London, Lawrence Livermore National Laboratory

  • J. Steven Steven Ross

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

  • Thomas D Chapman

    Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory

  • John D Moody

    Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory

  • Jason Wilson Bates

    Naval Research Laboratory, Naval Research Lab, U.S. Naval Research Lab

  • Andrew J Schmitt

    Naval Research Lab, Naval Research Laboratory, Plasma Physics Division, NRL, Plasma Physics Division, US Naval Research Lab, U.S. Naval Research Lab