FLASH simulations of laser-driven shock compression experiments on SiO₂

Recent high-energy-density (HED) experiments investigating the SIO₂ equation of state under laser compression deviate from theory predictions [1]. To better understand this discrepancy, we carried out experiments on coesite, a polymorph of quartz. However, artifacts present in the data have proven challenging to interpret. To disentangle the roles of potential target heterogeneities, such as glue layers, gaps, and edge effects, we carried out 1- and 2-dimensional FLASH simulations. These simulations allow us to track the evolution of the plasma plume and predict changes in laser absorption. They also enable visualization of photon trajectories through FLASH’s ray tracing capabilities. Direct comparison of simulated and experimental pressure-intensity relationships allows us to validate the simulation framework and assess how variations in target assembly can affect the observed experimental signatures. Our approach provides new insight into the origins of the artifacts in HED experiments and offers a framework for extending predictive modeling to more complex target designs.

[1] Shuai Zhang, Miguel A. Morales, et. al.; Nature of the bonded-to-atomic transition in liquid silica to TPa pressures. J. Appl. Phys. 21 February 2022; 131 (7): 071101