Accurate Modeling of 3D Effects in Laser-Driven Cylindrical Implosion Experiments

Laser-driven experiments at the National Ignition Facility produce extreme states of matter which are difficult to probe using current diagnostics. A cylindrical target geometry allows for direct imaging down the axis of the cylinder with x-ray radiography while also providing some compression and heating of the central material. We consider targets that utilized an Al marker layer and a low-density CH foam to provide a convergence ratio greater than five. A sinusoidal perturbation was machined on the inner surface of the Al layer to seed Rayleigh-Taylor instability growth during the convergence/deceleration phase. To understand these complex systems, accurate simulations are required to enable their design and analysis, and the simulation methods must always be tested and benchmarked against experimental data. This work leverages full 3D FLASH [B. Fryxell et al. (2000), P. Tzeferacos et al. (2015)] radiation-hydrodynamics simulations of these laser driven cylindrical implosions. The computational results compare well with the experimental data, which demonstrated significant 3D asymmetries from the axial non-uniformity of the laser drive. These findings highlight the need for complete 3D simulations of these types of experiments to accurately capture the physical behavior.