ON THE CIRCULAR-POLARIZATION IN PULSAR EMISSION

A model explaining the existence and properties of the circular polarization in pulsar emission is offered. It is based on the properties of waves excited in pulsar magnetospheres by possible plasma instabilities. The cyclotron instability developing due to the anomalous Doppler effect is carefully investigated. The following characteristics of the emission polarization are explained: if circular polarization exists it should be confined to small angles and observed in the core-type emission; the maximum intensity of circular polarization in the profile window is near the intensity maximum of the core-type emission; the sense-reversals of circular polarization in some pulsars and their absence in others; the correlation between circular polarization and position-angle swings; the behaviour of circular polarization in PSR 1541 + 09, 1702 - 19 and others.