On a plasma beam instability in a pulsar magnetosphere

The nearpulsar ultrarelativistic plasma is considered and beam instabilities, which may occur in such plasma are investigated. It is shown that for known now plasma parameters of pulsar magnetosphere the development of beam instability can progress only through hydrodynamic stage, the beam can be diffused at that. It is also shown that kinetic beam instability of longitudinal waves doesn't develop in nearpulsar ultrarelativistic electron-positron plasma with certain relativistic factors of beam and plasma. Nevertheless the hydrodynamic instability develops and even under the condition of wide pulse spread of the beam