Enhanced Laser-Energy Coupling with Small-Spot Distributed Phase Plates (SG5 650) in OMEGA Cryogenic Implosions

ORAL

Abstract

The ratio of the laser far-field spot diameter to the target diameter has been reduced in an attempt to mitigate cross-beam energy transfer and improve energy coupling. The 60 OMEGA beams were outfitted with new small spot (``SG5-650'') distributed phase plates (DPP's), with a diameter \textasciitilde 80{\%} of that of the standard SG5-850 DPP's, and used for cryogenic DT ice target implosions. The ablation-front trajectory, the backscattered laser energy, and the neutron bang time were found to be consistent with a 10{\%} increase in energy coupling. The hydrodynamic efficiency, defined as the ratio of the kinetic energy in the imploding shell to the laser energy, increased from 4.5{\%} to 5.0{\%}. However, an increase in hot electron production was observed, and evidence was seen in framing-camera images for increased hydrodynamic instabilities associated with the smaller DPP spots, limiting the implosion performance. Further experiments are required to study how to maintain the improved energy coupling while mitigating preheat and hydrodynamic instabilities. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.

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Authors

  • 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

  • D. Cao

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

  • R. C. Shah

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

  • 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

  • A.R. Christopherson

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

  • Dana Edgell

    Laboratory for Laser Energetics, University of Rochester

  • C.J. Forrest

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

  • V.Yu. Glebov

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

  • V.Yu. Glebov

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

  • Varchas Gopalaswamy

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

  • I.V. Igumenshchev

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

  • S. Ivancic

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

  • J.P. Knauer

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

  • O.M. Mannion

    University of Rochester

  • F.J. Marshall

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

  • Z.L. Mohamed

    University of Rochester

  • D. Patel

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

  • Hans Rinderknecht

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

  • M.J. Rosenberg

    U. of Rochester's Laboratory for Laser Energetics, LLE, University of Rochester, Laboratory for Laser Energetics, Laboratory for Laser Energetics, University of Rochester, Laboratory for Laser Energetics, U. of Rochester, Laboratory for Laser Energetics, University of Rochester

  • 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

  • C. Thomas

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

  • Sean Regan

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

  • Maria Gatu Johnson

    MIT, Massachusetts Institute of Technology, PSFC, MIT

  • J.A. Frenje

    MIT, MIT PSFC, Massachusetts Institute of Technology, PSFC, MIT

  • R. Petrasso

    Massachusetts Institute of Technology, PSFC, MIT, MIT