Pump-depletion Dynamics and Saturation of Stimulated Brillouin Scattering in Shock Ignition Conditions

ORAL

Abstract

Shock ignition (SI) is an alternative inertial confinement fusion scheme, which requires a strong shock to ignite a pre-compressed fusion capsule. In this concept, nonlinear laser-plasma instabilities can play an important role. The recent experiments conducted on OMEGA-EP laser facility demonstrated that stimulated Brillouin scattering (SBS) can $\sim$100\% deplete the first 0.5~ns of the spike laser pump. In this period, the pump-depletion moved from $0.01-0.02$ critical density ($n_{\rm c}$) region to $0.1 - 0.2~n_{\rm c}$ region. The dynamic pump-depletion was indicated from the shape of the laser-generated blast wave and the time-resolved stimulated Raman backscattering spectra. The pump-depletion dynamics can be explained by the breaking of ion-acoustic waves in SBS. The strong laser pump depletion would reduce the collisional laser energy absorption in SI but may limit the temperature of hot electrons which could benefit the electron shock ignition.

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Authors

  • Shu Zhang

    University of California San Diego

  • Jun Li

    Los Alamos National Lab, University of California San Diego

  • Sarah Muller

    General Atomics

  • Wolfgang Theobald

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

  • Chuang Ren

    University of Rochester, Laboratory for Laser Energetics

  • J.P. Palastro

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

  • C. Stoeckl

    University of Rochester, University of Rochester - LLE, Laboratory for Laser Energetics, University of Rochester, Laboratory for Laser Energetics, Laboratory for Laser Energetics, U. of Rochester, University of Rochester, NY 14623, USA

  • Timothy Filkins

    Laboratory for Laser Energetics

  • David Turnbull

    Laboratory for Laser Energetics, LLE

  • Dan Haberberger

    Laboratory for Laser Energetics

  • Michael Campbell

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

  • Riccrado Betti

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

  • Dimitri Batani

    Université de Bordeaux, Centre Lasers Intenses et Applications

  • Jocelain Trela

    Centre Lasers Intenses et Applications

  • Robbie Scott

    Rutherford Appleton Laboratory

  • Christine Krauland

    General Atomics, Lawrence Livermore National Laboratory

  • Farhat Beg

    University of California, San Diego, CER, UCSD Mechanical and Aerospace Engineering, University of California San Diego

  • Mingsheng Wei

    Laboratory for Laser Energetics, LLE