Measurements of inner shell pre-heat response in a double shell two-axis keyhole implosion

Recent DT Double Shell shots have used a 1.5 MJ reverse ramp laser pulse with a GDP coated Mo or W inner shell, with a >10¹⁴ yield. The double shell target is comprised of an outer aluminum ablator shell and an inner high-Z pusher shell, separated by a cushion of low-density foam. High energy Au L-shell photons are created in the gold bubble region of the hohlraum, these photons are high enough energy to penetrate the Al outer shell but are then absorbed by the higher Z inner shell. The deposited energy drives shocks into both the tamper and rest of the inner shell. This alters the density profile of the inner shell before the collision between the outer and inner shells. This can impact the overall kinetic energy transfer between shells and significantly alter the hydrodynamic instability properties of the inner shell during the rest of the implosion. We will present two-axis keyhole VISAR measurements of preheat induced motion of the inside of a GDP coated Mo shell prior to the arrival of the main shock, as well as NXS measurements characterizing Au L-shell emission from the gold bubble region.



*This work conducted under the auspices of the U.S. DOE by LANL under contract 89233218CNA000001