Shock Interactions in Double Shell Inertial Confinement Fusion Targets

Inertial confinement fusion (ICF) uses a pulsed, energetic driver (lasers, x-rays, or magnetic fields) to compress spherical capsules filled with deuterium-tritium (DT) fuel to

create a fusion reaction. The laser indirect-drive double shell ICF platform led by Los Alamos National Laboratory consists of two concentric shells, which form the capsule: a

low-density, low-atomic number outer shell, and a high-density, high-atomic number inner shell, with an extremely low-density foam cushion in between the two. This design provides a path to study burning plasma interactions, as the x-ray driven shock compression of a double shell could lead to a volume burn configuration in the DT fuel. Many shock interactions take place in such a target before burning plasma in the fuel is reached, such as hard x-ray preheat in the high-Z inner shell, the propagation of instabilities, and an uncertain equation of state response from porous, low-density foams and novel mixed materials (W and Be). While eventually the capsules will be imploded at the National Ignition Facility (NIF), we test multiple aspects of the shock physics on the OMEGA laser facility first. One such experiment employs the nonsteady waves sound speed platform to measure the Hugoniot and sound speed in a W-Be

mixture. This and other scaled-down experiments can tell us about the mixed EOS and instabilities caused by engineering features in double shell capsules and improve the

performance of experiments on NIF.