X-ray spectroscopy of high-energy density plasmas: theory and applications

X-ray spectroscopy is a powerful diagnostic of high-energy density plasmas. The science foundation is multidisciplinary and new developments in atomic physics models, Stark-broadened spectral line shapes, radiation transport, measurement techniques, and advanced data analysis methods have made a significant impact. The fidelity of atomic models has increased dramatically since the early days of plasma x-ray spectroscopy due to the present capability of computing customized databases of atomic structure and scattering data needed to feed kinetics models that compute plasma ionization and charged state distribution, atomic level populations, and photon-energy resolved emissivity and opacity. Detailed Stark-broadened spectral line shapes can now be calculated for complex K- and L-shell spectra, including satellite transitions, and are employed in spectroscopic quality radiation transport to model the emergent intensity distribution. Computing synthetic data to assess the validity and reliability of the spectroscopic method has become important as well as multi-objective data analysis driven by smart search and optimization algorithms that have enabled the extraction of the spatial distribution of plasma conditions. This talk will discuss the theoretical foundation of x-ray spectroscopy of high-energy density plasmas as well as several applications to experiments including advanced data analysis methods, the challenges that lie ahead, and the open questions that will drive new developments and applications.