A Single spark model for PSR J2144$-$3933

TL;DR

This paper explains the unique emission characteristics of PSR J2144$-$3933 using a single spark within the partially screened vacuum gap model, highlighting the role of non-dipolar magnetic fields and polar cap temperature regulation.

Contribution

It demonstrates that a single spark in the PSG model can account for the pulsar's single-component profile and emission features, emphasizing the importance of non-dipolar magnetic fields.

Findings

Single spark suffices to sustain critical temperature in PSR J2144$-$3933.

Observations support a centrally traversed emission beam by the line-of-sight.

No subpulse drifting observed, consistent with a single spark model.

Abstract

The partially screened vacuum gap model (PSG) for the inner acceleration region in normal radio pulsars, a variant of the pure vacuum gap model, attempts to account for the observed thermal X-ray emission from polar caps and the subpulse drifting timescales. We have used this model to explain the presence of death lines, and extreme location of PSR J2144$-$3933 in the $P-\dot{P}$ diagram. This model requires maintaining the polar cap near a critical temperature and the presence of non-dipolar surface magnetic field to form the inner acceleration region. In the PSG model, thermostatic regulation is achieved by sparking discharges which are a feature of all vacuum gap models. We demonstrate that non-dipolar surface magnetic field reduces polar cap area in PSR J2144$-$3933 such that only one spark can be produced and is sufficient to sustain the critical temperature. This pulsar has a single component profile over a wide frequency range. Single-pulse polarimetric observations and the rotating vector model confirm that the observer's line-of-sight traverses the emission beam centrally. These observations are consistent with a single spark operating within framework of the PSG model leading to single-component emission. Additionally, single-pulse modulations of this pulsar, including lack of subpulse drifting, presence of single-period nulls and microstructure, are compatible with a single spark either in PSG or in general vacuum gap models.