Nested titanium-aluminum implosions on the Z accelerator

Summary form only given. Analyses of Z-pinch spectral data and one-dimensional MHD simulations have indicated that much of the emissions from highly ionized and excited states in pinches originate in a hot core. In this case, significant re-absorption of high energy X-rays can occur in the cooler regions of the plasma, as discussed by Thornhill et. al. However, if the plasma is very structured with many localized regions emitting, this effect could be reduced and complicated by varying escape distances. To examine such effects, a series of experiments have been performed using rested arrays on the Z accelerator. Nickel-clad titanium arrays were employed, and on alternate shots, the inner and outer array was composed of aluminum. The location of the aluminum array was varied since it was not a priori possible to predict which location would result in aluminum being predominantly on the outside of the pinched plasma. Extensive side-on and end-on X-ray diagnostics were employed. These have revealed significant data on the dynamics of the implosions. No increase in X-ray yield was observed with the inclusion of aluminum; however, the yield did not decrease when aluminum was in the inner array. The yield decreased significantly when the aluminum was in the outer array. We will present the analysis of this data and comparisons to one-dimensional calculations.