Investigating at-scale MagLIF preheat on the NIF

Recent experiments with D2-filled gas pipe targets at the NIF have continued to investigate laser preheating at parameters relevant to 40+ MA MagLIF designs. The experiments span a range of 1.6-4.8 mg/cc fill densities, and measure time-resolved laser propagation and burnthrough in a 1 cm-long target. One of the most significant uncertainties in previous coupling estimates is the energy deposition into the tube entrance window material, which is predicted in simulations to be of order ~few kJ but which is difficult to measure directly. By employing the NIF Visar system to measure the shock strength when the heated plasma reaches the wall of the target, the total energy deposited into the gas can be more accurately determined. These measurements are compared with 2D and 3D Hydra simulations.



This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.