Modulational instability and evolution of inhomogeneous Langmuir fields in a plasma

Modulational instability and evolution of two types of the inhomogeneous Langmuir fields: a localized field and standing wave has been considered. It is shown that when exceeding the threshold already at the linear evolution stage near maxima of pumping intensity, time-narrowing density wells cavitons - with localized distrurbance of field in them - appear. Time of caviton formation is determined by the most inertial processes - plasma intrusion from the regions of pumping peaks at a sound velocity