Simulation of thermal response and ion deposition in the HAPL target chamber 1 mm tungsten armor layer using the improved BUCKY code

Abstract

Improved radiation hydrodynamics 1-D simulations were performed with the BUCKY code using new models for the plasma–wall interface and for ion source term transport. The new models were used to investigate the thermal response and ion implantation in a tungsten armor shell at a radius of 10.5 m with a thickness of 1 mm, which correspond to the nominal parameters for the high average power laser (HAPL) reactor target chamber. The simulations were performed using a chamber buffer gas of xenon at pressures of 8 μTorr and 8 mTorr. Two direct-drive target explosions were simulated: a 343 MJ empty foam target and a 365 MJ Pd–Au coated target. The simulations were run to 12.5 μs to ensure that all of the simulated ions were stopped in the tungsten armor. Surface temperature peaks due to X-rays, debris ions and kinetic ions were found for both the empty foam and the Pd–Au coated targets. Ion implantation results from the BUCKY simulations were compared to SRIM simulations of the same ion spectra to assess the validity of using BUCKY to estimate ion stopping in the tungsten armor. Parametric calculations were performed to ascertain the effect of buffer gas pressure on surface temperature rise in the tungsten armor.