Three-Dimensional Simulations of Machined Perturbation Profiles Subjected to the Richtmyer-Meshkov Instability: Mix Metrics Analysis and Comparison to Experiments

Shock-driven hydrodynamic instabilities play a major role in the performance of inertial confinement fusion targets. The presence of surface roughness in these targets, e.g., from machining, seeds instability growth, potentially leading to turbulence and mixing, degrading the conditions necessary to achieve thermonuclear burn. Recent data from the ModCons experimental campaign — performed on Omega EP with a singly shocked heavy-to-light interface (plastic and foam) — has observed shot-to-shot differences between six shots of the same nominal perturbation profile, suggesting that small variations in target fabrication may be important in the late-time turbulence and mixing. In this work, we simulate the evolution of three-dimensional surface roughness for these six machined perturbation profiles using the LANL code xRAGE. The results of the 3D simulations are then averaged out (in space) to produce 2D maps of mix metrics such as the density-specific volume covariance. The analysis is further quantified by comparing to 2D simulations with the BHR turbulence model.