An empirical model for the beams of radio pulsars

TL;DR

This paper presents an empirical model explaining the diversity of pulsar radio profiles by emission altitude variations near the last open field lines, successfully matching observations through Monte Carlo simulations.

Contribution

The model introduces a novel emphasis on emission altitude range as the key factor in pulse shape complexity, differing from previous transverse-focused models.

Findings

Model reproduces observed pulse profile diversity

Transition between simple and complex profiles explained by altitude changes

Monte Carlo simulations confirm model's consistency with real data

Abstract

Motivated by recent results on the location of the radio emission in pulsar magnetospheres, we have developed a model which can account for the large diversity found in the average profile shapes of pulsars. At the centre of our model lies the idea that radio emission at a particular frequency arises from a wide range of altitudes above the surface of the star and that it is confined to a region close to the last open field lines. We assert that the radial height range over which emission occurs is responsible for the complex average pulse shapes rather than the transverse (longitudinal) range proposed in most current models. By implementing an abrupt change in the height range to discriminate between young, short-period, highly-energetic pulsars and their older counterparts, we obtain the observed transition between the simple and complex average pulse profiles observed in each group respectively. Monte Carlo simulations are used to demonstrate the match of our model to real observations.