Proton Conversion Efficiency Measurements Relevant to Fast Ignition

ORAL

Abstract

We report on recent experimental and modeling studies of proton conversion efficiencies at laser intensities (10$^{19}-10^{20}$ W/cm$^2$) and pulselengths (0.5 to 5ps) relevant to the Proton Fast Ignition scheme. Experiments were performed on the Titan laser at LLNL using coated targets to investigate the effect of molecular composition on the proton beam flux. Erbium hydride targets provide a proton rich surface layer that minimizes depletion and improves conversion efficiency. The hybrid PIC code LSP (large-scale plasma) is used to self consistently model the processes of electron transport, field generation, and proton acceleration using realistic target parameters (i.e., density, spatial dimensions, and material composition) for these targets. LSP shows enhanced conversion efficiency with high-Z hydride targets due to the dependence of atomic mass on the partition of energy between ion species. *This work was performed under the auspices of the U.S. DOE by LLNL under contracts DEFG02-05ER54834, W-7405-Eng-48 No. DE-FC02-04ER54789 and DE-AC52-07NA27344.

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Authors

  • T. Bartal

    UCSD

  • F.N. Beg

    University of California, San Diego, University of California San Diego, UC San Diego, UCSD, Department of Mechanical and Aerospace Engineering, University of California San Diego

  • S. Chawla

    UCSD

  • D. Higginson

    UCSD

  • M.S. Wei

    UCSD

  • B. Westover

    University of California San Diego, UCSD

  • T. Yabuuchi

    UCSD, UCSD, USA, University of California, San Diego

  • M. Foord

    LLNL

  • D. Hey

    LLNL

  • M.H. Key

    LLNL, Lawrence Livermore National Laboratory

  • S. LePape

    LLNL

  • T. Ma

    University of California San Diego, UCSD, LLNL

  • A.J. Mackinnon

    LLNL, Lawrence Livermore National Laboratory

  • A.G. MacPhee

    LLNL

  • P.K. Patel

    LLNL, Lawrence Livermore National Laboratory

  • K.U. Akli

    General Atomics, GA

  • R.B. Stephens

    General Atomics, GA, General Atomics, San Diego

  • C.D. Chen

    MIT

  • R.R. Freeman

    The Ohio State University, The Ohio State University, Columbus, OH, OSU

  • E. Kemp

    OSU

  • D. Offermann

    OSU

  • V.M. Ovchinnikov

    OSU

  • L. Van Woerkom

    Physics Department, The Ohio State University, Columbus Oh 43210, The Ohio State University, Columbus, OH, OSU

  • Y.Y. Tsui

    Electrical and Computer Engineering, University of Alberta, Edmonton Canada, Dept. of Elec. and Computer Engr., Univ. of Alberta, Univ of Alberta, U of Alberta