Publications

2-D RMHD modeling assessment of current flow, plasma conditions, and doppler effects in recent Z argon experiments

Thornhill, J.W.; Giuliani, John L.; Jones, Brent M.; Apruzese, John P.; Dasgupta, Arati; Chong, Young K.; Harvey-Thompson, Adam J.; Ampleford, David A.; Hansen, Stephanie B.; Coverdale, Christine A.; Jennings, Christopher A.; Rochau, G.A.; Cuneo, M.E.; Lamppa, Derek C.; Johnson, Drew J.; Jones, Michael J.; Moore, Nathan W.; Waisman, Eduardo M.; Krishnan, Mahadevan; Coleman, Philip L.

By varying current-loss circuit parameters, the Mach2-tabular collisional radiative equilibrium 2-D radiation magnetohydrodynamic model was tuned to reproduce the radiative and electrical properties of three recent argon gas-puff experiments (same initial conditions) performed on the Z machine at Sandia National Laboratories. The model indicates that there were current losses occurring near or within the diode region of the Z machine during the stagnation phase of the implosion. The 'good' simulation reproduces the experimental K-shell powers, K-shell yields, total powers, percentage of emission radiated in α lines, size of the K-shell emission region, and the average electron temperature near the time-of-peak K-shell power. The calculated atomic populations, ion temperatures, and radial velocities are used as input to a detailed multifrequency ray-trace radiation transport model that includes the Doppler effect. This model is employed to construct time-, space-, and energy-resolved synthetic spectra. The role the Doppler effect likely plays in the experiments is demonstrated by comparing synthetic spectra generated with and without this effect.