Coster-Kronig mediated inner-shell X-ray lasers pumped by 20 fs, 100-TW-class lasers

Summary form only given. The development of keV X-ray lasers based on inner-shell atomic transitions requires extremely fast energy deposition on a target in order to effectively compete with the inherently fast (0.1-20 fs) atomic decay processes. The duration of ultrahigh peak power laser systems is now reaching this timescale. In principle, these systems can be used to produce sufficient duration and energy X-rays or electrons for pumping inner-shell transitions. In this paper X-ray laser schemes in which the Coster-Kronig Auger-process is the dominant lower level decay mechanism are described. Such systems have inherently short lower level lifetimes and under certain conditions can be inverted both with excitation by energetic electrons as well as X-rays. They are therefore relatively immune to secondary electron ionization and thus have dramatically reduced threshold conditions and simpler geometric considerations than previously proposed inner-shell laser schemes.