Simultaneous studies of K- and L-shell mid-atomic-number plasmas produced by Z-pinches

Abstract Z-pinches have been intensively studied for their applications to high energy density (HED) physics, x-ray sources, astrophysics, and inertial confinement fusion. Alumel (mostly Ni) double planar wire array (DPWA) Z-pinch experiments were performed on the Zebra generator at the enhanced current of 1.6 MA with an advanced setup of diagnostics to measure the temporal evolution of x-ray radiation from plasmas. The implementation of two time-gated spectrometers which recorded hard and soft x-ray radiation allowed for simultaneous studies of K-shell and L-shell radiating plasmas, respectively, in a single experiment. Two almost identical DPWA experiments established a wide observation window around the main x-ray burst. Overall, time-gated plasma spectroscopy provided more information on temporal evolution of ‘hot’ and ‘cold’ K-shell radiating plasmas compared to slowly evolving L-shell radiating plasma. In addition, new spectral features such as from hollow ions were observed and studied using the time-gated K-shell plasma spectroscopy, which is important for further investigation of exotic ion states in HED plasmas.