The propagation of two, three or more filaments in the background of a plane wave was considered. Based on the numerical solution of the truncated nonlinear Schrodinger equation the role of the background field, the formation of filamentation in the origin and maintaining of secondary filaments are demonstrated, as well as the possibility of growth in the number of filaments due to their breeding grounds, against the background of a plane wave. It is established that the intensity of the background field increases with the maximum number of filaments along the propagation path, but only up to a value of the intensity of background waves. With further increase in the intensity of the background wave, maximal number of filaments, formed along the route, decreases.
femtosecond laser radiation, multiple filamentation