Cryogenic-DT-Implosion Performance with Improved Target-Surface Quality

High fuel areal densities (\textit{$\rho $R}) are routinely achieved in low-adiabat cryogenic deuterium--tritium (DT) implosions on the OMEGA laser.\footnote{ V. N. Goncharov\textit{ et al.}, Phys. Rev. Lett. \textbf{104}, 165001 (2010).} While these \textit{$\rho $R}'s agree with 1-D hydrocode predictions, the measured yields have been lower than predictions, even when cross-beam energy transfer is included. The yield deficit is believed to be caused by nonuniformities on the target surfaces and in the laser-drive symmetry.\footnote{S. X. Hu\textit{ et al.}, Phys. Plasmas \textbf{17}, 102706 (2010).} A significant source of outer-surface perturbations has been identified and partially mitigated-condensable gases that freeze out on the surface of the capsule. Mitigating this source led to a consistent 2$\times $ improvement in the measured primary yield. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.