Design of a Polar-Drive, Alpha-Heating Platform for the National Ignition Facility

Polar drive (PD)\footnote{ S. Skupsky \textit{et al.}, Phys. Plasmas \textbf{11}, 2763 (2004).} allows one to conduct direct-drive--ignition experiments at the National Ignition Facility (NIF) while the facility is configured for x-ray drive. A PD-ignition design has previously been developed.\footnote{ T. J. B. Collins \textit{et al.}, Phys. Plasmas \textbf{19}, 056308 (2012).} A new, robust PD design has been developed with the goal of achieving alpha-heating and deuterium--tritium yields in excess of 10$^{16}$ neutrons at the NIF with the final optics and direct-drive cryogenic target positioner intended for subsequent PD-ignition experiments. This design uses a higher fuel adiabat, which precludes scaling to ignition but results in greater stability and experimental control, minimizing fuel--shell mix during the deceleration phase of the implosion. The new design also incorporates the effects of cross-beam energy transfer and nonlocal electron transport. This platform will make it possible to test radiation--hydrodynamic codes in preparation for PD-ignition experiments. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.