Circular polarization shows the nature of pulsar magnetosphere composition

TL;DR

This paper explores how circular polarization in pulsar emissions indicates a baryonic-mass plasma in the magnetosphere, challenging previous ion-proton plasma models and emphasizing low-altitude emission sources.

Contribution

It provides qualitative analysis linking polarization observations to plasma composition, supporting the presence of baryonic particles in pulsar magnetospheres.

Findings

Circular polarization suggests baryonic-mass plasma in pulsar magnetospheres.

Phase retardation between plasma modes is consistent with low-altitude emission.

Observations favor a baryonic plasma over ion-proton models.

Abstract

It has been argued in previous papers that an ion-proton plasma is formed at the polar caps of neutron stars with positive polar-cap corotational charge density. The present paper does not offer a theory of the development of turbulence from the unstable Langmuir modes that grow in the outward accelerated plasma, but attempts to describe in qualitative terms the factors relevant to the emission of polarized radiation at frequencies below 1 - 10 GHz. The work of Karastergiou and Johnston is of particular importance in this respect because it demonstrates in high-resolution measurements of the profiles of 17 pulsars that the relative phase retardation between the O- and E-modes of the plasma is no greater than of the order of pi. Provided the source of the radiation is at low altitudes, as favoured by recent observations, this order of retardation is possible only for a plasma of baryonic-mass particles.