Evolution of the interpretation of the X-ray spectrum originated from highly charged ions (HCI) produced in laboratory experiments, and space observations of cosmic X-ray sources.

Transition energies of highly charged ions is a topic of much interest in atomic physics. In the laboratory, the production of HCIs requires high technology plasma sources and precision measurements from dedicated spectrometers. The emission by HCIs is also of utmost interest for the interpretation of the spectrum from astrophysical sources; therefore, fundamental, for designing the tasks of recent and future space observatories. Here is a comparison that reports the recent historical collaboration between laboratory and space observations of cosmic X-ray sources.