Na‐like autoionizing levels: Plasma diagnostics and prospects for photopumped soft X‐ray lasers

We have investigated the kinetics of doubly excited sodium‐like copper states with 3131’ and 3141’ configurations, and the feasibility of photopumped x‐ray lasing schemes and plasma diagnostics using transitions from these levels. These x‐ray lasing schemes, like similar lasing schemes in Li‐like ions, have high quantum efficiency and potentially reduced radiative trapping effects. In addition, the satellite transitions emitted by these sodium‐like levels may provide valuable diagnostics of x‐ray laser plasmas.