DEVELOPMENT OF A NON-LTE SPECTRAL POSTPROCESSOR FOR DENSE-PLASMA SIMULATIONS WITH APPLICATION TO SPECTROSCOPIC DIAGNOSTICS IN SPHERICAL IMPLOSIONS AT NOVA

A new non-LTE spectroscopy post-processing package is described. The p ackage Processes dump files from 1 or 2-dimensional radiation-hydrodyn amics code simulations. Given the grid motion, temperatures, and ion d ensities contained in the dump files, as well as data from an arbitrar ily detailed atomic model, the post-processor calculates internally co nsistent detailed frequency dependent opacities and radiation fields. The radiation transport equation is solved in the S(n) approximation u sing lambda iteration. Sub-cycling is used to achieve a more accurate solution to both the kinetics and radiation field calculations. Line b roadening is included using Voigt widths based on the atomic rate coef ficients, and Stark widths are included for K-shell spectra. The Sobol ev escape factor approximation is available as an option. This post-pr ocessing package has been used to analyse spectra obtained recently at Nova with Ar doped deuterium filled capsules. The dopant was designed to be primarily a density diagnostic (via Stark broadening) but can a lso be used for temperature diagnosis as well. We have run this post-p rocessor with a wide array of atomic models for argon, ranging from on e containing only singly excited levels for the (important) hydrogenic , He-like, and Li-like sequences, to one containing a large number of doubly- and triply-excited levels in these sequences. We show a strong dependence of the degree of agreement between simulation and experime nt on the model complexity with only the most complex mode in close ag reement.