Oblique Shock Experiments on the OMEGA-EP Laser*

In inertial confinement fusion (ICF), understanding the evolution of hydrodynamic instability growth is an essential part of designing an implosion target that is robust to mix between the cold target shell and the hot fusion core. Early in time, shocks traversing the target amplify seed modulations through the slow growing Richtmyer-Meshkov (RM) and Kelvin-Helmholtz (KH) instabilities. These instabilities seed the faster growing Rayleigh-Taylor (RT) instability during the acceleration and deceleration phases of the implosion. We present an experimental platform designed to investigate coupling between the RM and KH instabilities by launching a planar shock through a polyamide-imide cylinder on the OMEGA-EP laser. The rear surface of the target has a single mode sinusoidal seed modulation that is machined on an interface that is at an angle with respect to the planar shock, creating an oblique shock breakout. The evolution of the rear surface modulation is measured using side-on x-ray radiography with a spherical crystal imager backlight by a copper k-alpha source. Experimental data will be presented along with comparisons with 1-D and 2-D simulation predictions.