X-Ray Spectroscopy of Highly Charged Ions in Laboratory and Astrophysical Plasmas

Summary

The Universe is rich with X-ray sources which can now be observed with unprecedented resolution using instruments on Chandra and XMM-Newton. In order to interpret their spectral signatures and derive reliable information regarding the physical characteristics and the dynamics of these objects and their environments, detailed spectral models have been developed which require vast amounts of highly accurate data on atomic collisional and radiative properties for ions in a broad range of ionization states. These data are usually obtained from theoretical calculations through which a large parameter space of physical conditions such as temperature and density can be explored. Critical to the reliability of these models is the careful benchmarking of the theoretically generated data through high-precision laboratory measurements. To provide a picture of the astrophysics, the goal is to develop a set of key spectroscopic diagnostics with an accuracy ( ∼ 5–10%) that is commensurate with the uncertainties in the highest quality astrophysical spectra. Using a broad band, high resolution X-ray microcalorimeter coupled to an EBIT, we are studying the behavior of highly charged plasma ions. Our goals for accuracy and reliability are now achievable and some of our results are presented here. A new technique for improving the measurement accuracy is also described.