ANALYZING TIME-RESOLVED SPECTROSCOPIC DATA FROM AN AZIMUTHALLY SYMMETRICAL, ALUMINUM-WIRE ARRAY, Z-PINCH IMPLOSION

A 90-wire, aluminum, z-pinch experiment was conducted on the Saturn ac celerator at the Sandia National Laboratories that exhibited azimuthal ly symmetric implosions and two x-ray bursts, a main burst and a subsi diary one. These bursts correlated with two consecutive radial implosi ons and are consistent with predicted magnetohydrodynamics behavior. A variety of time-resolved, accurately timed, spectroscopic measurement s were made in this experiment and are described in this paper. These measurements include (1) the pinch implosion time, (2) time-resolved p inhole pictures that give sizes of the K-shell emission region, (3) ti me-resolved K-series spectra that give the relative amounts of hydroge nlike to heliumlike to continuum emission, (4) the total and the K-she ll x-ray power outputs, and (5) time-resolved photoconducting diode me asurements from which continuum slopes and time-resolved electron temp eratures can be inferred. Time-resolved Ly-alpha and Ly-beta linewidth s are obtained from the spectra and inferences about time-resolved ion temperatures are also made. AII of these data correlate well with one another. A method is then presented of analyzing this data that relie s on the complete set of time-resolved measurements. This analysis uti lizes one-dimensional radiative magnetohydrodynamic simulations of the experiments, which drive z-pinch implosions using the measured Saturn circuit parameters. These simulations are used to calculate the same x-ray quantities as were measured. Then, comparisons of the measured a nd calculated data are shown to define a process by which different dy namical assumptions can be invoked or rejected in an attempt to reprod uce the ensemble of data. This process depends on the full data set an d provides insight into the structure of the radial temperature and de nsity gradients of the on-axis pinch. It implies that the first implos ion is composed of a hot plasma core, from which the kilovolt emission s emanate, surrounded by a cooler, denser shell, and it provides detai ls about the structure of the temperature and density gradients betwee n the core and shell regions. These results are found to be broadly co nsistent with an earlier, less detailed, data analysis in which plasma gradients are ignored. However, the ability to reproduce the full spe ctroscopic data in the present analysis is found to be sensitively dep endent on the radial gradients that are calculated.