Photoionization of Super Sonic Gas Jet Targets Utilizing the 1MA Zebra Generator.*

In astrophysical objects such as x-ray binary systems, active galactic nuclei, and black hole accretion disks a high-intensity broadband x-ray flux produces photoionized plasmas. Laboratory photoionized plasma experiments enable systematic studies relevant to astrophysics and provide data to test theory and benchmark modeling codes. An experimental platform has been developed to study photoionized plasmas via the photoionization of supersonic gas jets, using a 1MA class pulsed power generator. The gas jet targets are irradiated and ionized by a 25ns-duration x-ray flux produced by the implosion of a wire array. Neon, argon, and nitrogen gas jets have been investigated. Laser and x-ray diagnostics were used to probe the neutral gas jet as well as the photoionized plasma. Specifically, Mach-Zehnder interferometry at 266nm, air wedge interferometry at 266 and 532nm, and shadowgraphy at 266, 532, and 1064nm. The data from these measurements allowed us to determine the average ionization, charged state distribution, and map the topology of the neutral and ionized gas jets. Interferometry measured electron densities ~ 10¹⁸ - 10¹⁹cm^-3. X-ray spectroscopy showed neon photoionized plasmas with L-shell ions.