Spectral Line Identification of a Photoionized Silicon Plasma In Emission

Photoionized silicon plasma experiments were performed using the Z machine at Sandia National Laboratories. A spectrometer with high spectral resolution (λ/δλ~9200) was conceived to record emission from the expanding plasma. The data resolution is unprecedented for plasma emission and include detections of many previously unobserved spectral lines. The observations were made possible by a combination of a low-density plasma, highly resolving quartz crystal, minimum source size effect in the spherical geometry, and highly resolving x-ray film. These data compose the first set of benchmark emission spectra suitable to test theoretical assumptions related to the atomic data used in astrophysical models of accretion-powered photoionized plasmas. The data allow for measurements of relative wavelengths for Silicon emission lines which can be used to test model predictions for multiple silicon charge states (He-like to B-like) as well as level states within those charge states. We discuss our method to identify statistically significant emission line detections using multicomponent Gaussian decomposition. We also describe how the results will be used to expand astrophysical and laboratory based atomic databases with constrained uncertainties.