Experimental Measurements of Broadband HED Richtmyer-Meshkov Instability Growth

Hydrodynamic instabilities are ubiquitous on interfaces that interact with shocks. These instabilities are often seeded by surface roughness that is too computationally expensive to resolve directly. For broadband RM, it is expected that the RM growth rate will depend on the initial conditions so long as some of the modes remain linear. However, in low-energy-density RM experiments it is difficult to precisely prescribe an interface perturbation, so that measurements confirming this relationship have remained elusive. Here, we present Omega-EP experiments measuring the dependence of broadband RM growth on the power law describing the perturbation.

In these experiments, we machined a 2D broadband perturbation onto a PAI interface abutting foam with m=-1, -2, and -3 power laws. Phases of individual modes were kept consistent across perturbations so that differences in instability growth are due to the power law change alone. We will present experimental results and analysis as well as comparisons to xRAGE simulations.

*This work conducted under the auspices of the U.S. DOE by LANL under contract 89233218CNA000001