Capsule symmetry and hydrodynamic stability of high density carbon and plastic ablator implosion designs on the National Ignition Facility

Achieving areal density and temperature conditions necessary for hot spot ignition at the National Ignition Facility (NIF) requires careful control of capsule performance (implosion velocity, fuel adiabat) and hot spot shape. Capsules using high density carbon (HDC) and plastic ablators driven by adiabat-shaped X-ray profiles are designed to reach the alpha heating regime. A comparison of the relative stability of these designs was made using TROLL radiation hydrodynamics simulations of single-mode perturbation linear growth at the ablation front and fuel-ablator interface. Performing designs have to associate both hohlraum performance and capsule stability. Two-dimensional integrated simulations have been performed to evaluate how changes to the hohlraum (size, gas fill density, shape, beam balance) and to the laser pulse (picket, foot drive, pulse length) impact the HDC and plastic capsule performance and implosion symmetry. The combination of all these effects is used to help guide future designs for NIF and the Laser Mega Joule facility.