K and XUV signatures of high K-yieldstructured AR puff loads

Summary form only given. Structured 12 cm diameter Ar gas puff loads have produced Rayleigh-Taylor stable implosions and K-yields close to 1D hydrocode predictions. In order to optimize the designs of future loads, it is important to identify the reasons for these stable implosions. Diagnostics of the K-shell (3 keV < E < 5 keV) emitting mass are fairly well developed, but most of the load mass emits radiation at sub-keV photon energies. XUV diagnostics provide information about this cooler mass. We have measured for the first time the axially-resolved XUV spectrum (0.1 < E < 1 keV) and the axially-resolved emission time history (or "zipper") in discrete energy bands (i.e. 650 100 eV). In this paper, we review the axially-resolving XUV diagnostic and discuss the observed correlations between the XUV and K-shell data. Generally, the highest K-shell yields are produced at axial positions where the initiation of the XUV emission precedes the K by >15 nsec and rises to a peak relatively slowly (~15 nsec). At locations where the XUV emission rises abruptly (les5 nsec), close in time to when the K-emission initiates, the K-emission is weaker. This observation is consistent with calculations that predict improved K-emission when shock preheating of the load mass is followed by quasiadiabatic compression