The magnetic field topology in the reconnecting pulsar magnetosphere

TL;DR

This paper investigates how magnetic field topology and reconnection processes in pulsar magnetospheres influence particle acceleration, pulsar braking, and observable radiation, highlighting the role of magnetic field closure efficiency and pair formation.

Contribution

It introduces a link between magnetic field topology, reconnection electric fields, and pulsar braking index, providing new insights into particle acceleration limits in pulsar magnetospheres.

Findings

Magnetic field closure efficiency affects pulsar braking index.

Reconnection electric fields accelerate particles to ~10^16 eV.

Synchrotron reaction does not limit maximum particle energy.

Abstract

We show that toroidal magnetic field annihilation in the equatorial current sheet of the pulsar magnetosphere is related to how fast poloidal magnetic field lines close as we move away from the light cylinder. This determines the reconnection radial electric field which directly accelerates particles in the neutral layer inside the equatorial current sheet. The efficiency of poloidal magnetic field closure near the light cylinder may be measurable through the pulsar braking index. We argue that, the lower the efficiency of pair formation, the higher the braking index. We also argue that synchrotron radiation reaction in the neutral layer does not inhibit the accelerated particles from reaching the maximum energy of about 10^16 eV available in the open pulsar magnetosphere.