OBSERVATION OF KL-]LL X-RAY-SATELLITES OF ALUMINUM IN FEMTOSECOND LASER-PRODUCED PLASMAS

The aluminum KL satellite emission spectrum excited by suprathermal el ectrons originating from the nonlinear interaction of a high intensity subpicosecond laser pulse with a solid target is obtained. The measur ed integrated intensity of the KL-->LL satellites relative to the Ka l ine is found to be 30% higher than in previous experiments performed w ith continuous, monoenergetic electron excitation. A double-vacancy cr eation by the shake-off process and a two step inner-shell ionization mechanism are investigated to interpret the data. An upper estimate of the preheating electron temperature is deduced from the analysis.