High-Resolution Planar-Foil In-Flight Density Profile Measurements on OMEGA EP

The in-flight density profile of the driven shell in an inertial confinement fusion implosion is an important quantity that depends on the shell adiabat and affects shell convergence and peak density. An experimental platform has been developed on OMEGA EP at the Laboratory for Laser Energetics to access similar physics by measuring the density profile of a planar foil. A 1 × 0.4 × 0.04-mm CH foil was driven by a 3-ns UV beam with 3 kJ focused to a 750-µm spot using a distributed phase plate. The density profile in the driven direction was measured using x-ray radiography and a Fresnel zone plate to achieve a spatial resolution of ~1 µm. Spatial blur from the movement of the driven target was minimized by using a 20-ps laser to drive the x-ray probe (Ti He_α = 4.75 keV). The interaction was probed at four time delays, starting from before the shock breaks out of the foil to the density profile during in-flight acceleration. The status of analysis, platform improvements, and comparison to DRACO hydrodynamic simulations will be presented.