ARES Simulations of Inverted Corona Experiments at the OMEGA Laser Facility

Inverted corona experiments, wherein lasers are focused onto the inside walls of a capsule lined with deuterated plastic (CD), are a promising candidate for use as neutron sources in laser experiments. While such targets are expected to achieve significant yields at NIF energy scales, the effects of specific target design elements (such as liner thickness) on yield are not yet well-understood and -characterized. 2-D hydrodynamic simulations of inverted corona experiments indicate that the ion-ion mean free path is very long, necessitating more robust computational methods. However, more physically complete PIC simulations are computationally expensive; this raises the question of whether a hydrodynamic code with molecular diffusion and mix models could serve as a useful middle ground. ARES is a massively parallel, multi-dimensional, multi-physics code developed and maintained by Lawrence Livermore National Laboratory (LLNL). In this study, we used ARES’ well-established and benchmarked molecular diffusion and dynamic mixing packages to investigate the effect of diffusion and mix on neutron yield, and to compare simulated results with an experiment performed at OMEGA exploring the effect of CD liner thickness on neutron yield in DD and ³He filled inverted corona targets. We found that while ARES overpredicts the neutron yields by roughly a factor of 10, its predictions of yield scaling with liner thickness closely match those experimentally observed.