Аннотация:Plasma created by femtosecond laser pulse of high intensity can be used as the brilliant source of high energy electrons, ions and X- or -rays. In most cases, laser pulses with high contrast are used for particles acceleration. But, it has been shown, that changing parameters of pre-plasma layer on the surface of the target can significantly increase electron energies. We have shown that the required pre-plasma layer parameters can be obtained in the presence of ns duration pre-pulse (e.g., high ASE level). The aim of this work was to study the processes taking place in this case.