Progress in Platform Development and Combined Analytical Methods for Studying Hydrodynamic Instability Growth in High Energy Density Conditions at NIF

We describe developments in experimental platform design and analytical methods for studying hydrodynamic instability growth in high-energy-density plasmas at the National Ignition Facility. The experimental platform utilizes dual, laser-driven halfraums with target configuration of high-density plastic ablators and low-density carbon foam, incorporating machined single-mode sinusoidal perturbations at the foam-plastic interface. Selection of ablation thicknesses and foam densities provides extended measurement windows with reduced late-time shock interference, allowing observation of Richtmyer-Meshkov and Rayleigh-Taylor instability evolution from linear through nonlinear regimes toward turbulence. Diagnostic capabilities combine multi-physics ARES simulations with experimental effects to generate synthetic radiographs for comparison with experimental data. Fourier analysis of periodic structures within Kelvin-Helmholtz whorls differentiates between nonlinear regime growth and pre-turbulent behavior where initial wavelength signatures disappear. Analysis methods applied to experimental radiographs identify transition-to-turbulence signatures that compare with Implicit Large Eddy Simulation models, providing insight into fine-scale hydrodynamic instability dynamics in HED conditions.