Effects of Porosity in Meteorite Materials: Hydrodynamics Code Simulations of Gas Gun Shock-Wave Experiments

We use the multi-physics code ALEGRA to model how porosity ranging from 0-50% effects the evolution of temperatures (T), pressures (P), and quench rates in 1.5-3.0 km/s high-velocity impacts of meteorite materials. The simulations follow the passage of the initial shock wave, the evolution of T and P during wave reflections, and the time frames these conditions persist relative to one another. These 2-D Eulerian mesoscale simulations constrain the conditions that occurred in a 25-shot series of hypervelocity impact recovery experiments using a 30 mm, 2-stage light gas gun. The experiments are designed to be representative of what is observed and recovered in shocked meteorites. Validation and detail are added through comparison of the simulation with observations from scanning and high-resolution transmission electron microscopic images of the recovered experimental material. We discuss the implications the dynamic conditions have on the extent of melt vein development and preservation of high-pressure phases within the heterogenous meteorite material. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.