Updates to the Laser Gate Experiment for Increasing Preheat Energy Coupling in Magnetized Liner Inertial Fusion (MagLIF)

Magnetized Liner Inertial Fusion (MagLIF) is an inertial confinement fusion concept being tested at Sandia National Laboratories (SNL). MagLIF targets feature a laser entrance hole covered by a thin (few-micron-thick) window to hold the pressurized fusion fuel in place. There are energy losses as a preheating laser beam ablates through this plastic window. Laser-window interactions reduce heating efficiency and mix window and target materials into the fuel. To reduce these losses and improve fusion yield, we are implementing a system to remove this plastic window before the laser beam passes through the window opening. This window removal method is referred to as "Laser Gate".  We have demonstrated a Laser Gate proof of concept at the University of Michigan (UM) [S.M. Miller et al., RSI 91, 063507 (2020)]. More recently, we have added an interferometer to measure the density of the gas/fuel as it escapes from the target. This UM test stand will allow us to further study window opening dynamics, assess system jitter, and determine design specifications for upcoming preheat experiments at SNL. We will report on the results of our intermediate experiments at UM as well as our designs for integrating this version of Laser Gate into the already established preheat platform at SNL.