Inverse Bremsstrahlung Absorption

ORAL  · Invited

Abstract

Inverse bremsstrahlung absorption was measured based on transmission through a finite-length plasma that was thoroughly characterized using spatially resolved Thomson scattering. Expected absorption was then calculated using the diagnosed plasma conditions while varying the absorption model components. To match data, it is necessary to account for: (i) the Langdon effect; (ii) laser-frequency (rather than plasma-frequency) dependence in the Coulomb logarithm, as is typical of bremsstrahlung theories but not transport theories; and (iii) a correction due to ion screening. Radiation-hydrodynamic simulations of inertial confinement fusion implosions have to date used a Coulomb logarithm from the transport literature and no screening correction. We anticipate that updating the model for collisional absorption will substantially revise our understanding of laser-target coupling for such implosions.

*This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856, the University of Rochester, and the New York State Energy Research and Development Authority.

–

Publication: D. Turnbull et al., Phys. Rev. Lett. 130, 145103 (2023).

Presenters

  • David P Turnbull

    • University of Rochester
    • University of Rochester Laboratory for Laser Energetics

Authors

  • David P Turnbull

    • University of Rochester
    • University of Rochester Laboratory for Laser Energetics

  • Joseph D Katz

    • Laboratory for Laser Energetics
    • University of Rochester - Laboratory for Laser Energetics
    • University of Rochester

  • Mark W Sherlock

    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Laboratory

  • Laurent Divol

    • Lawrence Livermore Natl Lab
    • LLNL
    • Lawrence Livermore National Laboratory

  • Nathaniel R Shaffer

    • Lab for Laser Energetics

  • David J Strozzi

    • Lawrence Livermore Natl Lab
    • LLNL
    • Lawrence Livermore National Laboratory

  • Arnaud Colaitis

    • CELIA

  • Dana H Edgell

    • LLE

  • Russell K Follett

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

  • Kyle R McMillen

    • University of Rochester

  • Pierre A Michel

    • Lawrence Livermore National Laboratory
    • LLNL
    • Lawrence Livermore Natl Lab

  • Avram L Milder

    • University of Alberta

  • Dustin H Froula

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