Mitigating the Joint Feature in Double Shell Implosion Simulations*

Double shell capsules provide an attractive alternative in inertial confinement fusion experiments due to their potential for achieving a low-convergence, robust burn. However, symmetry degradation and accompanying reduced fuel confinement harm capsule performance due to the joint between the two hemispheres of the outer shell. The gap widens during irradiation and this perturbation grows and imprints onto the inner shell during the collision. xRAGE Eulerian radiation-hydrodynamic simulations predict significant reductions in deuterium–tritium fusion yields compared to joint-less simulations when the depth of the outer joint is increased. We explore how the technique of plating the insides of the outer gap with gold can mitigate the impact of this feature. Gold-plating in quantities comparable to or exceeding the “missing” outer shell mass shows promise toward restoring both implosion symmetry and yield closer to the joint-less levels. We show that x-ray synthetic radiographs can capture the shape and symmetry retention in the outer and inner shells. Finally, the performance of alternative coating materials is discussed.