Detection of anomalous self-reversal of emission lines of a laser plasma formed on the surface of a solid target in a normal atmosphere

Anomalous self-reversal of the aluminium emission lines 396.1 and 394.4 nm was detected experimentally. The lines emitted by the hotter regions of a laser plasma on the surface of an aluminium target did not coincide with the absorption lines of the same atoms in colder regions of the plasma plume. Consequently, the centre of a dip in the emission lines, resulting from self-absorption, was not at the line centre. A qualitative explanation of the effect was based on a shock-wave-induced Stark shift of an emission line of a hot plasma region.