On the collective curvature radiation

TL;DR

This paper investigates the collective curvature radiation mechanism in pulsar magnetospheres, showing that certain wave modes cannot be emitted and emphasizing the importance of wave polarization and dielectric properties in understanding pulsar radio emission.

Contribution

It demonstrates that electromagnetic waves with a single cylindrical harmonic cannot be produced by the collective curvature radiation, highlighting the role of wave polarization and dielectric tensor in the process.

Findings

Single harmonic waves cannot be radiated by the mechanism.

Wave polarization is crucial and must be derived from wave equations.

Dielectric permittivity tensor describes the medium's electromagnetic response.

Abstract

The paper deals with the one possible mechanism of the pulsar radio emission, i.e., with the collective curvature radiation of the relativistic particle stream moving along the curved magnetospheric magnetic field lines. It is shown that the electromagnetic wave containing one cylindrical harmonic exp{is{\phi}} can not be radiated by the curvature radiation mechanism, that corresponds to radiation of a charged particle moving along curved magnetic field lines. The point is that the particle in vacuum radiates the triplex of harmonics (s, s \pm 1), so for the collective curvature radiation the wave polarization is very important and cannot be fixed a priori. For this reason the polarization of real unstable waves must be determined directly from the solution of wave equations for the media. Its electromagnetic properties should be described by the dielectric permittivity tensor \^{\epsilon}({\omega},k,r), that contains the information on the reaction on all possible types of radiation.