Characteristic Effects of Pulsed Power Generators of Different Architecture on the Implosion Dynamics of Mid-Z Double Planar Wire Arrays

Abstract

Planar Wire Arrays (PWAs) have been studied on both the University of Michigan’s (UM) low-impedance Linear Transformer Driver (LTD) MAIZE generator (0.1 Ω, 0.5-1 MA, and 100-250 ns) and the University of Nevada, Reno’s (UNR) high-impedance Zebra Marx bank generator (1.9 Ω, 1 MA, 100 ns). The results with Low-Z Aluminum and High- Z Tungsten Double Planar Wire Arrays 1 (DPWAs) were compared earlier; thus Brass (an alloy of Mid-Z elements Copper and Zinc) DPWAs were selected for study to get a more complete understanding of Low- to High-Z DPWA implosions on MAIZE. As the LTD is a relatively new form of pulsed power generator, comparing results from traditional generators (such as Marx banks) will help us to better understand both technologies. Experimental diagnostics included an absolutely calibrated filtered polycrystalline diamond detector (PCD), filtered Si-diodes, x-ray pinhole cameras, spectrometers, and optical shadowgraphy systems. Time-dependent inductance modelling on the MAIZE LTD was derived from the measured current trace 1 . Radiative and implosion dynamics of Brass DPWAs on the MAIZE LTD are presented and compared to previous results on the Zebra Marx generator 2 . Implosions on the MAIZE LTD featured a longer than expected current risetime dependent on the load inductance, a longer pinching process and x-ray emission time, and resulted in L-shell plasmas comparable in characteristics with previous studies on Zebra.