Angular distribution of SRS backscatter in NIF ignition experiments

POSTER

Abstract

Modeling the SRS backscatter from NIF hohlraums provides a path to a better understanding of the under-dense plasma conditions created within, which have yet to be measured directly. The spatial location of SRS amplification regions influences the amount of refraction that the scattered light undergoes, and thus its angular distribution exiting the hohlraum. Here we describe how we use pF3D [R. L. Berger et al., Phys. Plasmas 5, 4337 (1998); C. H. Still et al., Phys. Plasmas 7, 2023 (2000)], SLIP [P. Michel et al., Phys. Plasmas 17, 056305 (2010)] and a simple ray-tracing application to model the near-field (angular) distribution of SRS backscatter in NIF ignition experiments. We compare these results to the measurements made by the improved time-dependent NBI (Near-Backscatter Imager) and the FABS (Full-Aperture Backscatter) diagnostics [J. D. Moody et al., Rev. Sci. Instrum. 81, 10D921 (2010)].

*This work was performed under the auspices of the U.S. DOE by LLNL under contract DE-AC52-07NA27344.

Authors

  • Edward Williams

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore National Lab.

  • J.D. Moody

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore National Lab.
    • LLNL

  • P. Michel

    • Lawrence Livermore National Laboratory
    • LLNL
    • Lawrence Livermore National Lab.

  • Denise Hinkel

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore National Lab.

  • A. Bruce Langdon

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore National Lab.

  • Steven Langer

  • Laurent Divol

    • LLNL
    • Lawrence Livermore National Laboratory