Measurement of inflight shell areal density perturbations in NIF capsule implosions near peak velocity

ORAL

Abstract

Quantitative measurements of shell-RhoR perturbations in capsules near peak implosion velocity (PV) are challenging. An external backlighter samples both sides of the shell, unless a re-entrant cone is used (potentially perturbing implosion). Emission from the hot core, after shock-stagnation and prior to PV, has been used as a self-backlighter, providing a means to sample one side of the capsule. Adding high-Z gas ($\sim$ 1{\%} Ar) to the capsule fill in Symcaps ($^{4}$He), has produced a continuum backlighter with significant increase in emission at photon energies $\sim$ 8 keV over nominal fills. From images of the transmitted self-emission, above and below the K-edge of an internally doped Cu layer, we infer the growth at PV of imposed perturbations (100 nm amplitude, mode 40).

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Authors

  • B.A. Hammel

    Lawrence Livermore National Laboratory

  • L. Pickworth

    Lawrence Livermore National Lab, Lawrence Livermore National Laboratory

  • Vladimir Smalyuk

    Lawrence Livermore National Laboratory, LLNL, Lawrence Livermore Natl Lab

  • A.G. MacPhee

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • H.A. Scott

    Lawrence Livermore National Laboratory

  • H.F. Robey

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • Maria Alejandra Barrios

    Lawrence Livermore National Laboratory

  • S.P. Regan

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