Hot spot formation and stagnation properties in simulations of direct-drive NIF implosions

[摘要] We investigate different proposed methods of increasing the hot spot energy and radius in inertial confinement fusion implosions. In particular, shock mistiming (preferentially heating the inner edge of the target's fuel) and increasing the initial vapor gas density are investigated as possible control mechanisms. We find that only the latter is effective in substantially increasing the hot spot energy and dimensions while achieving ignition. In all cases an increase in the hot spot energy is accompanied by a decrease in the hot spot energy density (pressure) and both the yield and the gain of the target drop substantially. 2D simulations of increased vapor density targets predict an increase in the robustness of the target with respect to surface perturbations but are accompanied by significant yield degradation.

[发布机构] Plasma Physics Division, Naval Research Laboratory, Washington; DC; 20375, United States^1

[关键词] 2D simulations;Control mechanism;Direct drive;Energy density;Gas density;Hot spot;Surface perturbations;Yield degradation