Scaling Laser Preheat For Maglif With The Z-Beamlet Laser

Optimizing the performance of the Magnetized Liner Inertial Fusion (MagLIF) platform on the Z pulsed power facility requires coupling greater than 2kJ of preheat energy to an underdense fuel in the presence of an applied axial magnetic field ranging from 10 to 30T. Achieving the suggested optimal preheat energies has not been experimentally achieved so far. In this work, we explore the preheat design space for cryogenically cooled MagLIF targets, which represent a viable candidate for increasing preheat energies. Using 2D and 3D HYDRA MHD simulations, we first discuss the various physical effects that occur during laser preheat, such as laser energy deposition, self-focusing, and filamentation. After identifying the changes that different phase plates, gas-fill densities, and magnetic fields bring to the aforementioned physical effects, we, then, consider higher laser energies that are achievable with modest upgrades to the Z Beamlet laser. Finally, with a 6.0-kJ upgraded laser, 3D calculations suggest that it is possible to deliver 4.25kJ into the MagLIF fuel, resulting in an expected deuterium neutron yield ofYDD similar or equal to 1.5 x1014, or roughly 50kJ of DT equivalent yield, at 20-MA current drive. This represents a 10-fold increase in the currently achieved yields for MagLIF.