Fuel--Shell Mix and Pressure Measurements Based on X-Ray Continuum Emission from Isobaric Implosion Cores on OMEGA

ORAL

Abstract

At a spectral energy matched to the anticipated hot-spot temperature range, the x-ray emissivity of an imploded target hot spot is dependent almost entirely on pressure. In this way, the hot-spot pressure at the time of peak emission can be inferred from the spatially resolved core emission. The pressure and temperature dependences of the x-ray emissivity and the neutron production rate explain a simple scaling of the total filtered x-ray emission as a power of the total neutron yield for target implosions of similar design over a broad range of shell implosion adiabats. Excess emission from less-stable, low-adiabat implosions (above the level expected from this neutron-yield scaling) attributed to the higher emissivity of shell carbon mixed into the hot spot, indicates ``fuel--shell'' mix fractions in the 2{\%} to 5{\%} range. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and the Office of Fusion Energy Sciences Number DE-FG02-04ER54786.

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Authors

  • R. Epstein

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

  • F.J. Marshall

    • Laboratory for Laser Energetics, U. of Rochester

  • V.N. Goncharov

    • Laboratory for Laser Energetics, U. of Rochester

  • R. Betti

    • Fusion Science Center and Laboratory for Laser Energetics, U. of Rochester

  • R. Nora

    • Fusion Science Center and Laboratory for Laser Energetics, U. of Rochester

  • A.R. Christopherson

    • Fusion Science Center and Laboratory for Laser Energetics, U. of Rochester