Circular Polarization in Pulsars due to Curvature Radiation

TL;DR

This paper extends the curvature radiation model for pulsars to include detailed emission geometry, predicting polarization characteristics and their relation to emission modulation and source distribution.

Contribution

It introduces a generalized model that accounts for emission geometry and predicts polarization behavior, including the correlation between polarization angle swing and circular polarization sign reversal.

Findings

Circular polarization's antisymmetric type appears with emission modulation.

Model predicts correlation between polarization angle swing and circular polarization sign reversal.

Simulation of pulse profiles based on the extended curvature radiation model.

Abstract

The beamed radio emission from relativistic plasma (particles or bunches), constrained to move along the curved trajectories, occurs in the direction of velocity. We have generalized the coherent curvature radiation model to include the detailed geometry of the emission region in pulsar magnetosphere, and deduced the polarization state in terms of Stokes parameters. By considering both the uniform and modulated emissions, we have simulated a few typical pulse profiles. The antisymmetric type of circular polarization survives only when there is modulation or discrete distribution in the emitting sources. Our model predicts a correlation between the polarization angle swing and sign reversal of circular polarization as a geometric property of the emission process.