Multifilament arrays from terawatt femtosecond beam over an extended atmospheric path

This paper presents results of experimental study of the stochastic and regularized filamentation of terawatt femtosecond radiation on a distances 1–40 m in the atmosphere. The robust array of femtosecond filaments were observed if the initial beam was modulated with four hole amplitude mask and each sub beam contains peak power in the certain range. The distance of a stable spatial structure formation was found to be much less than the value deduced from the Marburger formula. It was shown that the distance of filament array formation is determined by the laser radiation diffraction at each hole in the amplitude mask.