Experimental Quantification of Shock Front Velocity Non-Uniformities in Indirectly Driven Wetted Foams with the OMEGA High-Resolution Velocimeter (OHRV)

Foams printed using 2-Photon Polymerization (2PP) and wetted with liquid fuel provide a promising new target platform for understanding target degradation mechanisms in inertial confinement fusion (ICF) implosions. These wetted foam targets are potentially cheaper and quicker to produce than solid ice layered targets, enabling rapid fielding of dense-fuel implosions that have potential applications in Inertial Fusion Energy. Experimental characterization of wetted foams to benchmark simulations is vital to the development of this target technology. Through two days of experiments using OMEGA’s Capseed Campaign platform, planar shocks were propagated through DD-wetted foams, and the transmitted shock fronts were imaged with the OHRV and the Active Shock BreakOut (ASBO) diagnostics. The shock-front nonuniformities and hydrodynamic instabilities seeded by various wetted foam samples were quantified, characterizing the impact of varying pore structures, densities, and thicknesses. Data analysis has enabled the benchmarking of HYDRA simulations of wetted foams via the timing of shock breakouts and the measurement of overall velocity perturbation. Experimental images also demonstrate spatial imprint of pore structures upon transmitted shock fronts. These results provide a more complete understanding of whether wetted foams may prove to be a tunable platform for investigating hydrodynamic instabilities in ICF implosions, and inform the design of wetted foam target platforms for IFE applications. This work is supported by the IFE-STAR STARFIRE Contract B663014. Part of this work was prepared by LLNL under Contract No. DE-AC52–07NA27344, and supported by LLNL LDRD 24-SI-003 and 23-ERD-027.