Radiation Transport in Saturn Targets Used for Polar Direct Drive

Saturn targets, spherical capsules placed within an equatorial low-$Z$ ring, are of interest for polar-direct-drive ignition experiments on the NIF using just the indirect-drive beam ports. Radiation from the ring to the capsule is calculated using a new, view factor-like radiation transport model in the 2-D hydrocode \textit{SAGE} that includes full directional and spectral information. This model provides improved agreement with experimental measurements on OMEGA of the drive uniformity of Saturn targets with a CH ring and a deuterium-filled CH capsule. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-92SF19460.