Nonlinear stage of the two-stream instability

Spatial-time behaviour of chaotically located inhomogeneities is investigated after the application of a strong electric field making electrons drift at the speed which is several times higher than the sound velocity. Each inhomogeneity increases its amplitude, simultaneously tapering off in electron drift direction. As far as electron concentration in an inhomogeneity is slighty different from the background one, the inhomogeneity moves at the speed of electric drift. When the concentration grows several times as compared to the background one, the inhomogeneity starts moving at the speed of ionic sound and its further growth stops