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.

*This work is conducted under the auspices of U.S. DOE NNSA under the NLUF program with award number DE-NA0002730, DE-NA0003600 and DOE Office of Science under the HEDLP program with award number DE-SC0014666.

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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