Time-Integrated Synthetic X-Ray Spectroscopy for Stainless Steel Wire Array $Z$-Pinches

Abstract

We have used a collisional-radiative spectroscopic model to generate a stainless steel (SS) atomic model to analyze the implosion dynamics of an array of SS wires on the Z and/or refurbished Z accelerator at the U.S. Sandia National Laboratories. This approach combines the completeness of highly averaged Rydberg state models with the accuracy of detailed models for all important excited states. Our atomic model includes a very large number of levels and atomic structure data, as well as excitation, ionization, and recombination level coupling. We have investigated the ionization dynamics and generated K- and L-shell spectra using the conditions in the Z accelerator, as calculated by a 1-D nonlocal thermodynamic equilibrium (LTE) radiation hydrodynamics model. This investigation using more detailed and accurate atomic models supersedes earlier spectroscopic simulation of K-shell SS spectra to analyze spectra on the Z accelerator. The non-LTE populations are obtained by generating the detailed atomic data for Fe, Ni, and Cr, and Mn ions, the constituents of SS. Analysis of our spectra using self-consistently generated data from the flexible atomic code shows excellent agreement with experimental data of shots Z581 and Z1860. We have also included level-specific dielectronic recombination from H- to He-like ions and inner-shell excitation rates from excited states of He-like ions in our atomic model and investigated the Ly <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">¿</sub> satellite lines that are useful for diagnosing Doppler broadening in a <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z</i> -pinch plasma at stagnation.