Characterization of Space and Time Resolved Electron Density in the Photoionized Plasma Gas Cell Experiment at Z

The photoionized plasma gas cell experiment is an established platform to make at-parameter (ξ>>1 ergs cm s^-1) measurements of plasma properties for benchmarking astrophysical modeling codes. The experiments are performed on the Z Machine at Sandia National Labs where a cell filled with neon gas is driven by the broadband x-ray flux produced by a wire array z-pinch implosion. The recent fielding of the photonic Doppler velocimetry (PDV) diagnostic for measuring space- and time-resolved electron density¹ has confirmed the existence of a hydrodynamically unperturbed photoionized plasma that is driven only by radiation². We model the experiment with the 1D radiation hydrodynamics code HELIOS-CR and present a comparison of experimental and simulation electron density time histories to assess the qualitative and quantitative accuracy of the simulation predictions. The results suggest that the experiments qualitatively agree with the simulations, although there are discrepancies in the time evolution and spatial distribution of the electron density. ¹K. J. Swanson et al RSI 93, 043502 (2022), ²G.S. Jaar et al HEDP (submitted, 2023).