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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.

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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