Neon photoionized plasma experiments at Z and Zebra

We discuss two experiments to study the atomic kinetics in astrophysically relevant photoionized plasmas. Both experiments employ the intense x-ray flux of a wire-array Z-pinch to heat and backlight neon photoionized plasmas. The Z Machine produces up to 200 TW of x-ray power in less than 10 ns. A cm-scale gas cell is placed near the pinch and filled with atom number densities of 10¹⁷ to 4x10¹⁸ cm^-3. Windows along the line of sight thru the cell permit an x-ray absorption measurement showing K-shell line absorption from Be- to H-like neon ions, revealing a highly ionized neon plasma. At the Zebra generator, the x-ray flux is lower power but longer in duration. The gas is positioned closer to the pinch as a super-sonic gas jet with densities of 10¹⁸ cm^-3. Absorption spectra here also show K-shell line absorption but from C- to He-like neon ions. Analysis of the spectra in both cases yields ion areal densities and charge state distributions that can be compared with simulation results from atomic kinetics codes. The electron temperature extracted from Li-like ion level population ratios can be used to test heating models of photoionized plasmas.