ELECTRON NUMBER DENSITY-MEASUREMENTS IN MAGNESIUM LASER-PRODUCED PLUMES

Interferometry has been used to investigate the spatio-temporal evolut ion of electron number density following 248 nm laser ablation of a ma gnesium target. Fringe shifts: were measured as a function of laser po wer density for a circular spot obtained using a random phase plate. L ine averaged electron number densities were obtained at delay times up to similar to 100 ns after the laser pulse. Density profiles normal t o the target surface were recorded for power densities on target in th e range 125-300 MW cm. (C) 1998 Elsevier Science B.V.