Influence of the polar cap current on pulsar polarization

TL;DR

This paper models how polar cap currents influence pulsar radio emission polarization, revealing shifts in intensity and polarization features, and explaining the origin of circular polarization types.

Contribution

It introduces a new model incorporating polar cap-current effects on magnetic field perturbation affecting pulsar polarization.

Findings

Polar cap current causes shifts in intensity components and polarization angle inflection points.

The model explains the origin of symmetric and antisymmetric circular polarization.

Under certain conditions, the trailing emission component is stronger than the leading one.

Abstract

We have developed a model for the polarization of curvature radiation by taking into account the polar-cap-current induced perturbation on the dipolar magnetic field. We present the effects of the polar cap current on the pulsar radio emission in an artificial case when the rotation effects, such as aberration and retardation, are absent. Our model indicates that the intensity components and the polarization angle inflection point can be shifted to either the leading or the trailing side depending upon the prevailing conditions in the viewing geometry, the non-uniformity in source distribution (modulation), and the polar cap-current-induced perturbation. Also, we find evidence for the origin of symmetric-type circular polarization in addition to the antisymmetric type. Our model predicts a stronger trailing component compared to that on the leading side of a given cone under some specific conditions.