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Center for Nonlinear Studies |
The UNR Physics Department features a diverse range of theoretical and experimental capabilities pertaining to spectroscopic plasma modeling and diagnostics. This presentation focuses on three areas of our current interest: 1) Collaboration on CHEMEOS - the LTE chemical-picture-based equation-of-state model used by the LANL ATOMIC code. Recent work has resulted in substantial speed-ups for this module, which is essential for opacity table generation. Additional performance improvements are currently under way as we implement alternative numerical solution methods. Some of these new techniques also allow the use of better plasma microfield physics in CHEMEOS, which has been hitherto rendered impractical due to large computation costs. 2) Recent experiments performed at the Rutherford Appleton Laboratory (RAL) modeled with our POLAR code (in conjunction with RAL's electron kinetics capabilities) demonstrate the diagnostic potential of polarization-based spectroscopy for anisotropic plasmas with the observed polarized Ly-alpha sulphur lines. Also, an ongoing collaboration with LANL aims at generalizing the underlying atomic collision and kinetics theory applicable to modeling of polarized line emissions and widening its capabilities. 3) Experiments at UNR's Nevada Terawatt Facility provided the first application of backlighter absorption spectroscopy of Al pinch plasma during its relatively cold initial ablation phase. Atomic kinetics and spectroscopic modeling, in conjunction with 2D MHD simulations, provided encouraging results in our efforts to characterize the plasma density and temperature conditions during this early stage of the pinch implosion.
Host: James Colgan, T-1, 5-0291, jcolgan@lanl.gov