Abstract
The dielectronic satellite transitions, originating on the 2s2p 3P and 2p2 3P doubly excited levels of helium-like Ar XVII, are identified in the spectrum from the laser-imploded core plasma of an argon filled glass microballoon. The intensities of these transitions are consistent with inner-shell excitation from the AR XVII 1s2s 3S and 1s2p 3P metastable levels. This implies that the Ar XVII ionisation stage is overheated and is undergoing transient ionisation in the core plasma.