Quasi-linear theory of Cherenkov-drift instability: Application for radio pulsars
Institute of Astronomy, University of Zielona Góra, Lubuska 2, 65-265 Zielona Góra, Poland
2 Center for Plasma Astrophysics, Abastumani Astrophysical Observatory, Al.Kazbegi ave. 2a, Tbilisi 380060, Georgia
Corresponding author: D. Shapakidze, firstname.lastname@example.org
Accepted: 4 July 2002
We present a plasma model for formation of discontinuous position-angle curves observed in some radio pulsar profiles. The model is based on the polarization properties of radio waves excited by Cherenkov-drift instability developing in pulsar magnetospheres. The radiation is confined in a cone of emission and consists of two orthogonally polarized waves. Examination of a quasi-linear stage of Cherenkov-drift instability shows that the excitation mechanism provides the modes with different spectral energy densities depending on the direction of . As a pulsar rotates, an observer's sight-line track crosses different mode-predominated areas on the base of the emission cone. Transition of the sight-line track from one mode-predominated area to another results in the formation of pulsar polarization fluctuations observed in polarization angle distribution displays and average waveforms.
Key words: stars: pulsars: general / polarization / radiation mechanisms: non-thermal / plasmas / instabilities
© ESO, 2002