Pulsar Magnetosphere Dynamics

TL;DR

This paper analytically explores pulsar magnetosphere configurations, revealing how plasma density influences the transition between open and closed states, potentially linking pulsar periods to magnetosphere dynamics rather than rotation.

Contribution

It provides analytical solutions for different pulsar magnetosphere configurations and reexamines stability conditions, proposing a new perspective on pulsar period origins.

Findings

Analytical solutions for open and closed magnetosphere configurations.

Reconsideration of the Goldreich Julian stability condition.

Magnetosphere dynamics may influence pulsar periods.

Abstract

With the neutron star rotating under a stationary magnetic field generating unipolar induction, charges are driven to the pulsar surface according to their signs, and are uploaded to the magnetosphere along the magnetic field lines. In the presence of an electron-positron plasma, the pulsar magnetosphere is represented by a unique magnetohydrodynamic (MHD) plasma. The pulsar equation of force-free equilibrium is solved analytically for two configurations. The first one is a light cylinder guided jet-like open magnetosphere, and the second one is a closed magnetosphere within the light cylinder. The Goldreich Julian condition for the stability of the closed magnetosphere (dead zone) is reconsidered which indicates transition of the closed magnetosphere to the open one as the electron-positron plasma density builds up. This suggests that the pulsar period could be the result of magnetosphere dynamics rather than the pulsar rotation.