Experiments exploring the effect of prescribed roughness on Richtmeyer-Meshkov growth in HED shock-tube targets

The LANL Multi-Shock (MShock) campaign on the NIF explores the Richtmeyer-Meshkov (RM) growth of initially solid, prescribed perturbation profiles after undergoing multiple shocks. In the ongoing Same-sided successive-shock (S4) experiments of this campaign the shock tube system is shocked twice from the same side at a time delay through a hybrid direct and indirect laser drive platform. Theory predicts many different cases for the growth of a twice-shocked sinusoidal perturbation depending on the perturbation scale and shock energy, some of which have been confirmed experimentally in a recent publication from this campaign. Recent experiments have explored the growth of single- and multi-mode perturbations under the effects of small-scale roughness to test whether these growth cases still hold. To reduce the number of shots needed on the NIF we also developed a scaled experimental analog for the Omega-EP laser to test the direct-drive growth. We present data from both the Omega and NIF experiments, with initial analysis of the effect of small-scale roughness on the growth rate.