  Optical emission spectroscopy is used to study the dynamics of the plasma
generated by pulsed-laser irradiation of a MgB2 target, both in vacuum and at
different Ar buffer gas pressures. The analysis of the time-resolved emission
of selected species shows that the Ar background gas strongly influences the
plasma dynamics. Above a fixed pressure, plasma propagation into Ar leads to
the formation of blast waves causing both a considerable increase of the
fraction of excited Mg atoms and a simultaneous reduction of their kinetic flux
energy. These results can be particularly useful for optimizing MgB2 thin film
deposition processes.

Superconductivity