High-Z Coatings Produce Significant Improvements in the Fusion Burn of Laser Driven ICF Implosions

Recent experiments on the Omega Laser Facility have demonstrated that the absolute number of neutrons and the yield-over-clean parameters show significant increases for implosion targets that have ablators with thin ($\sim $ 200-400 Ang.) high-Z layers on the outer surface. In the experiment, 850 micron diameter, 20 micron thick, CD shells where imploded on a low adiabat. The laser pulses where shaped such that a low foot, first compressed the target and a subsequent one nanosecond high intensity top-hat pulse accelerated and imploded the target. As was demonstrated in earlier NRL experiments,\footnote{S.P. Obenschain et al., Phys. Plasmas 9, 2234 (2002).} the reduction of laser imprint may be responsible for improving the performance of these implosions. Results from the latest implosion experiments, computer simulations, and their analysis will be reported.