Diagnosing K- and L-shell spectra from wire array implosions on refurbished Z

Summary form only given. Advances in diagnostics at the refurbished Z facility at Sandia National Laboratories (SNL) now allow spatially and temporally resolved spectra to be obtained, with improved signal-to-noise ratios. Z-pinch simulation models have also improved, due both to substantial advances in the understanding of the underlying physics, and to the development of more detailed and accurate atomic databases. We will examine K- and L-shell data obtained from the copper nested wire-array SNL shot Z1975, and compare it with data obtained from a simulation using the 1-D DZAPP radiation-hydrodynamics code. Since lines of Ni, Fe and Cr were observed in the experimental spectra, we performed the calculations with an appropriate mixture of these elements. In the present analysis, we find support for an alternative K-alpha mechanism which competes with the usual e-beam driven model, wherein K-shell photons from hot plasma on or near the axis are absorbed in a dense, cool annular envelope via inner-shell photoionization. The resulting electronic relaxation of the absorbing ion produces the K-alpha radiation. By generating radially resolved synthetic spectra from a fully self-consistent calculation of K-shell vacancy formation, a diagnostic is obtained which can help differentiate between beam generated and photon driven K-alpha radiation.