A Pulsational Model for the Orthogonal Polarization Modes in Radio Pulsars

TL;DR

This paper extends a pulsational model of radio pulsars to include polarization, proposing that non-radial oscillations modulate two orthogonal polarization modes, explaining observed polarization features.

Contribution

It introduces a model incorporating orthogonal polarization modes modulated by stellar pulsations, explaining polarization in pulsar radio emissions.

Findings

Model reproduces observed polarization patterns.

Superposition of modes explains orthogonal polarization angles.

Provides a framework for polarization variability in pulsars.

Abstract

In an earlier paper, we introduced a model for pulsars in which non-radial oscillations of high spherical degree (\el) aligned to the magnetic axis of a spinning neutron star were able to reproduce subpulses like those observed in single-pulse measurements of pulsar intensity. The model did not address polarization, which is an integral part of pulsar emission. Observations show that many pulsars emit radio waves that appear to be the superposition of two linearly polarized emission modes with orthogonal polarization angles. In this paper, we extend our model to incorporate linear polarization. As before, we propose that pulsational displacements of stellar material modulate the pulsar emission, but now we apply this modulation to a linearly-polarized mode of emission, as might be produced by curvature radiation. We further introduce a second polarization mode, orthogonal to the first, that is modulated by pulsational velocities. We combine these modes in superposition to model the observed Stokes parameters in radio pulsars.