Design of First Magnetized Hohlraum-Driven Implosions on NIF

The first magnetized, hohlraum-driven implosions on NIF -- or any facility -- are planned for the end of 2020. The goal is to demonstrate field compression in the implosion, following the MHD frozen-in law, which will be diagnosed by improved capsule nuclear performance (higher yield and temperature). These will be deuterium gas-filled capsules based on the ``BigFoot'' campaign, and use about 900 kJ of laser energy (about half of NIF's maximum). To facilitate soak-through of the externally-imposed, predominantly axial field, especially against inward radial JxB motion, a hohlraum with much higher electrical resistivity than the typical gold or uranium is needed. A novel gold-tantalum alloy has been developed for this purpose, with the first shots using a 2:8 Au:Ta mixture (atomic). We present radiation-MHD modeling of this design with the Lasnex code. Based on this, we expect DD neutron yields (2-4) x 10$^{\mathrm{13}}$ and burn-weighted ion temperature of 3.5 -- 4 keV, with an imposed 30 Tesla field. This should be 30-50{\%} higher in yield, and 0.5 keV in T$_{\mathrm{ion}}$, than an unmagnetized analog. The first two shots will vary the laser cone fraction (inner-beam vs. total power), to tune the implosion shape, and the third shot will be an unmagnetized repeat of one of these shots.