Intense Laser-to-Fast-Electron Coupling Efficiency in Wedge-Shaped-Cavity Targets

ORAL

Abstract

The interaction of ultra-intense lasers with hollow re-entrant cone targets is an important aspect of the fast-ignition scheme in inertial confinement fusion. Information on the spectrum of the $\sim $MeV electrons and the efficiency with which they are generated is required. We report on experiments of $\sim $5-J, $\sim $0.5-ps, $\sim $1 $\times $ 10$^{19}$ W/cm$^{2}$ laser pulses interacting with wedge-shaped-cavity targets. Spatially and spectrally resolved K-shell emission measurements from small-mass, Cu wedge-shaped-cavity targets with dimensions of $\sim $200 $\times $ 100 $\times $ 20 \textit{$\mu $}m$^{3}$ are reported for various opening angles and laser polarizations and are compared to flat-foil targets in the refluxing geometry.\footnote{P. Nilson \textit{et al}., Phys. Plasmas \textbf{15}, 056308 (2008).} This work was supported by U.S. Department of Energy under DE-FC52-08NA28302 and No. DE-FG02-05ER54839.

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Authors

  • W. Theobald

    • Laboratory for Laser Energetics, U. of Rochester

  • P.M. Nilson

    • Laboratory for Laser Energetics, U. of Rochester

  • J.F. Myatt

    • Laboratory for Laser Energetics, U. of Rochester

  • B. Eichman

    • Laboratory for Laser Energetics, U. of Rochester

  • S. Ivancic

    • Laboratory for Laser Energetics, U. of Rochester

  • C. Stoeckl

    • Laboratory for Laser Energetics, U. of Rochester

  • C. Ren

    • Laboratory for Laser Energetics, U. of Rochester

  • J.A. Delettrez

    • Laboratory for Laser Energetics, U. of Rochester

  • J.D. Zuegel

    • Laboratory for Laser Energetics, U. of Rochester

  • T.C. Sangster

    • Laboratory for Laser Energetics, U. of Rochester

  • V. Ovchinnikov

    • Ohio State University

  • L. Van Woerkom

    • Ohio State University

  • R.R. Freeman

    • Ohio State University

  • R.B. Stephens

    • General Atomics