Multidimensional Numerical Investigation of NIF Saturn PDD Designs with 3-D Laser Ray Tracing

The Laboratory for Laser Energetics continues to validate the use of the NIF and the LMJ in the x-ray-drive configuration for direct-drive-ignition experiments. Progress in this area indicates that polar direct drive (PDD) is a viable and attractive option for achieving ignition on these megajoule-class laser systems. Recent work has focused on the implementation of the Saturn PDD illumination scheme, which, employing an equatorial CH ring as a plasma lens, attempts to minimize target perturbations due to the absence of the equatorial beams in the x-ray-drive laser configuration. This paper will examine the implementation of the standard ``all-DT'' direct-drive-ignition design with a fixed CH equatorial ring. Previous work\footnote{ R. S. Craxton \textit{et al}., Phys. Plasmas \textbf{12}, 056304 (2005).} employed 2-D hybrid \textit{SAGE}--\textit{DRACO} calculations and indicated minimal performance degradation from 1-D results. We will report on recent 2-D hydrodynamic \textit{DRACO} simulations, examining the effects of the Saturn PDD illumination as modeled with fully integrated 3-D ray-trace models. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement DE-FC52-92SF19460.