The structure of the Laser Entrance Hole in NIF Ignition gas-filled hohlraums

ORAL

Abstract

At the National Ignition Facility (NIF), the energy from 192 laser beams is converted to an x-ray drive in a gas-filled hohlraum. The drive heats and implodes a fuel capsule. The laser beams enter the hohlraum via laser entrance holes (LEHs) at each end. The LEH size decreases as heated plasma from the LEH material blows radially inward but this is largely balanced by hot plasma in the laser deposition region pushing radially outward. Compared to models, the LEH size is larger than predicted. In addition, the plasma in the LEH region is hotter than predicted. Instead of being at the radiation temperature of about 300 eV, it is at an electron temperature of 1 to a few keV. The experimental measurements for this conclusion are discussed. Data on the LEH as a function of laser pulse shape, gas fill, and energy transfer are presented.

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Authors

  • M.B. Schneider

    LLNL, Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • T. Doeppner

    Lawrence Livermore Natl Lab, LLNL, Lawrence Livermore National Laboratory

  • C.A. Thomas

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • K. Widmann

    LLNL, Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory

  • S.A. Maclaren

    Lawrence Livermore National Laboratory, Lawrence Livermore Nat'l Lab, Lawrence Livermore Natl Lab

  • N.B. Meezan

    Lawrence Livermore National Laboratory, LLNL, Lawrence Livermore Natl Lab

  • P.M. Bell

    Lawrence Livermore Natl Lab

  • L. Benedetti

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab, LLNL

  • D.K. Bradley

    Lawrence Livermore National Laboratory, LLNL, Lawrence Livermore Natl Lab

  • Debra Callahan

    Lawrence Livermore National Lab, Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory

  • D. Eder

    Lawrence Livermore Natl Lab

  • J.H. Hammer

    Lawrence Livermore National laboratory, Lawrence Livermore Natl Lab

  • D.E. Hinkel

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • Oggie Jones

    LLNL, Lawrence Livermore National Laboratory, Lawrence Livermore National laboratory, Lawrence Livermore Natl Lab

  • Pierre Michel

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • J.L. Milovich

    LLNL, Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • John Moody

    LLNL, Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • A.J. Moore

    AWE, Atomic Weapons Establishment

  • Hye-Sook Park

    LLNL, Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • Joseph Ralph

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab, LLNL

  • S.P. Regan

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

  • D.J. Strozzi

    Lawrence Livermore National Laboratory, LLNL, Lawrence Livermore Natl Lab

  • R.P.J. Town

    Lawrence Livermore National Laboratory, Lawrence Livermore National Laboratory, Livermore, CA 94550, Lawrence Livermore Natl Lab, LLNL