Radiation from Tungsten Z-pinches influenced by using the alternating W and mid-atomic-number wires

Previously, it was demonstrated that compact wire arrays of 3-6 mm diameter/width are excellent radiation sources and can be useful for novel ICF applications, however currently there is very limited research on them. This study focuses on hard x-ray non-thermal inner-shell emission from compact cylindrical wire arrays (CCWA) and presents the analysis of radiation from tungsten (W) experiments performed on the 1 MA Zebra at the same conditions. Two W CCWA of 6 mm diameter with a similar array mass and the same number of wires (one with 24 W wires and another with alternating 12 W and 12 brass wires) are analyzed. Brass wires were chosen because characteristic W L-shell lines and Cu and Zn K-shell lines occupy the same spectral region between 1 and 1.6 Å, which makes their simultaneous observation possible using time-gated hard x-ray spectroscopy. A comprehensive comparison of x-ray diode signals, time-gated x-ray pinhole images and hard x-ray spectra, as well as soft x-ray spectra is presented to gain better understanding of changes in radiation from W Z-pinches when using alternating W and mid-atomic-number wires.