Numerical Simulations of Shock-Release OMEGA EP Experiments*

Release of shocked material from the inner side of the shell after the shock breakout is an important process in an inertial confinement fusion implosion that affects formation of the hot spot and thereby the implosion performance. Experiments on OMEGA EP at the Laboratory for Laser Energetics were performed to measure the low-density profile of the plasma in the rarefaction wave that follows the shock breakout from the back side of a CH shell driven by two OMEGA EP beams. The shell trajectory was measured using x-ray radiography. The low-density plasma inside the rarefaction wave was measured using 4w interferometry and angular filter refractometry. Results of radiation–hydrodynamic code DRACO simulations of the evolution of the density profile in the rarefaction wave will be presented and compared with the experimental data. Sensitivity of the density profile to the equation of state will be discussed.