Edge effects in molybdenum-encapsulated molten silicate shock wave targets

The customary acoustic calculation used to design shock wave equation of state targets may be inapplicable when the sample is enveloped in a container that has a higher shock impedance than the sample being studied. In this case the edge effect is compressional, and could travel faster than the speed of sound. We present computations of the nonlinear wave interactions that occur at the sample-container interface of molybdenum-encased molten silicate shock wave targets. In all cases considered here, the edge effect is acoustic despite the higher shock impedance of the container. The computational method is an extension of a conservative Eulerian finite difference scheme for two materials in two dimensions that is based on a second-order Godunov method. This new method includes adaptive mesh refinement, a volume-of-fluid interface tracking algorithm, and a Mie-Grüneisen equation of state to describe liquids and solids in the hydrostatic limit.