Progress in Indirect-Drive Inertial Confinement Fusion Experiments

Summary form only given. Results from the first NIF indirect-drive ICF experiments and Omega experiments testing new hohlraum and capsule designs are described. In the area of laser-hohlraum coupling, the effects of laser beam smoothing by spectral dispersion (SSD) and polarization smoothing (PS) on the beam propagation in long scale gas-filled targets has been studied at NIF at plasma scales relevant to indirect drive low Z filled ignition hohlraum designs. At Omega, a NIF-relevant high electron temperature gas-filled hohlraum platform has been developed for laser-plasma coupling studies. In the area of hohlraum energetics, isolated and integrated measurements of albedo and conversion efficiency have been performed on well characterized multi-element ("cocktail") hohlraum wall materials predicted to improve coupling efficiency. In parallel, a joint energetics and symmetry campaign testing new foam-filled ignition hohlraum designs and laser entrance hole shields in a NIF-like multicone illumination geometry has begun. We are also testing the hydrodynamic stability of more efficient Cu-doped Be capsule ablators and the hydrodynamic effects of fuel fill-tubes using X-ray absorption and emission imaging on hohlraum-driven surrogate capsules. Finally, the first set of high convergence implosions in NIF-relevant >250 eV hohlraums with NIF-like hohlraum-to-capsule coupling ratios have been performed, demonstrating good coupling and symmetry