Radiation-Mix Interaction at a Hydrodynamically Evolving Interface*

The Hohlraum Wall Heating (HWH) Campaign, conducted on the National Ignition Facility (NIF), studies the interaction of radiation and mix at a hydrodynamically evolving interface, such as a simultaneously ablating and radiating hohlraum wall. Studying these basic physics interactions and validating radiation-hydrodynamic codes improves our ability to understand and model the hohlraum radiation field, which is used to drive a large variety of High Energy Density Physics and Intertial Confinement Fusion experiments. In an effort to diagnose radiation and mix interactions, the HWH campaign has developed a simultaneous burn-through and radiography measurement platform, consisting of a hohlraum driving a three-layer foam package, where the middle layer is high-Z and Rayleigh-Taylor unstable with respect to a plastic tamping layer. A data set of burn-through measurements has been collected to bound the deviation of radiation transport across a spectrum of single- and multi-mode interfaces.  Corresponding radiographs of the mixing interfaces are obtained in both hot (transonic package) and cold (subsonic, control package) radiation environments to discern the interaction effects. Here, we summarize the results of the first half of the campaign, including the design and qualification of the experimental platform, the rippled-interface data set, and a comparison with 2D and 3D simulations.