K- and L-shell spectra of stainless steel X-pinches with notable effect of interwire angle

Due to \textit{Chandra}'s x-ray data capabilities, laboratory-produced plasma spectroscopy can be benchmarked against astronomical radiation and used as a diagnostic in astrophysical research. X-ray Fe and Ni spectra of astrophysical interest are studied using four-wire, 830 $\mu $g stainless steel (Fe: 69{\%}, Ni: 9{\%}, Cr: 20{\%}) X-pinches on the 1 MA Zebra Generator, where the interwire angle is varied between 31 and 62.5 degrees. Harder x-ray (1.6-2.3 {\AA}) K-shell Fe, Ni and Cr spectra included both ``hot'', ionic (T$_{e} \quad \ge $ 1.5 keV) and ``cold'', characteristic (T$_{e}$: 10-30 eV) lines, indicating a much colder plasma and the existence of an electron beam. For the smaller interwire angle, K-shell emission intensifies, producing both stronger ionic and characteristic lines. Softer x-ray spectra between 8-13 {\AA} include L-shell spectra dominated by 3-2 Ni and higher Rydberg (n$\to $2; n $\ge $ 4) Fe lines. Plasma conditions are estimated using Fe, Ni, and Cr non-LTE spectral models. In addition, shadowgraphy exhibits the formation of jets in the middle of the cross-point region and orthogonal to the wires in the load with an almost column-like plasma resembling a single wire for the 31 degree load. Work was supported by NNSA under DOE grant DE-NA0003047