Simulations of an Argon Z-Pinch Implosion with Time-Dependent Non-LTE Population Kinetics

Three argon gas-puff implosions were performed on the Z-machine at Sandia National Laboratories. These three loads had the same density profile from an 8 cm diameter nozzle, a 1 mg/cm mass, and had a 2.5 cm length. The experiments produced similar K-shell radiative power pulses and yields [1]. Simulations with the 2-D Radiation MHD code Mach2 were able to reproduce the experimental K-shell powers, yields, and emission region. It was also shown that the ratio of the argon Ly $\alpha$ to He plus intercombination (IC) lines from the simulation had good agreement to the experiments after peak K-shell power; however, the simulation's line ratio was higher prior to peak K-shell power. The authors attribute the difference to 3-D effects or on the implicit assumption of steady-state population kinetics [2]. This presentation will illustrate the effect of time-dependent level populations on the K-shell radiation from simulations using the NRL DZAPP code. DZAPP is a coupled 1-D MHD, detailed non-LTE atomic physics with radiation transport, incorporating a transmission line circuit. The argon line ratios and K-shell power pulses from the steady-state and time-dependent populations will be presented and compared with experiment.