The Effect of Helium on Burn in Directly Driven Glass Capsules

ORAL

Abstract

Experiments on the Omega laser confirm the previous observation (Rygg \textit{et al.} (\textit{Phys. Plasmas}, \textbf{13}, 052702 (2006)) of an abnormal degradation of D+D(n) and D+$^{3}$He(p) yields in hydrodynamically equivalent capsules as the $^{3}$He fraction is increased. The degradation remained using $^{4}$He. These implosions used either 23 kJ of laser energy in a 1000ps square pulse, or 13 kJ in a 600ps pulse, onto 900 micron diameter, $\sim $ 4.3 micron thick glass shells filled with 10 atm of deuterium or hydrodynamically equivalent mixtures with He. Measured ion temperatures would be the same for all mixtures in hydrodynamically equivalent capsules. For the 1000ps implosions they are. But for 600ps implosions the ion temperature increases with $^{3}$He concentration, showing a deviation from equivalency. Work supported by US DOE/NNSA, performed at LANL, operated by LANS LLC under Contract DE-AC52-06NA25396.

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Authors

  • Douglas Wilson

    • Los Alamos National Laboratory

  • George A. Kyrala

    • Los Alamos National Laboratory

  • J.F. Benage Jr.

    • Los Alamos National Lab
    • Los Alamos National Laboratory

  • Frederick Wysocki

    • Los Alamos National Laboratory

  • Johan A. Frenje

    • MIT
    • Massachusetts Institute of Technology

  • V. Glebov

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

  • Samuel Roberts

    • Laboratory for Laser Energetics, U. of Rochester

  • Warren J. Garbett

    • Aldermaston Weapons Establishment