X-ray line emissions from tamped thin aluminum targets driven by subpicosecond-duration laser pulses

We report on atomic kinetics and X-ray line spectra modeling work of plasmas generated by high-intensity, ultrashort-duration pulsed lasers. Our work is motivated by the need to analyze and interpret experiments with laser-irradiated layered targets performed at the Max-Planck-Institut für Quantenoptik. The focus of this Paper is on the theoretical characterization of the properties of X-ray line emissions as signatures of plasma conditions. Our model considers several spectral features with detailed attention paid to atomic kinetics, intrinsic spectral lineshapes in a high-density plasma environment (in particular Stark broadening and line shift effects), and spectroscopic-quality radiation transport (opacity effects). We apply our model to the analysis of time-integrated K-shell aluminum X-ray line spectra and time-resolved total line intensities obtained from the layered targets. Modeling calculations indicate that red line shifts observed in these experiments cannot be explained by shifts in the centers of gravity of composite spectral features due to blending with enhanced satellite contributions, but are consistent with intrinsic line shift effects in both resonance and satellite lines. We also investigate the sensitivity of our results to the selection of one of three adopted models for laser-energy deposition and transport within the target.