Simulations of pulsar wind formation

TL;DR

This paper presents the first self-consistent 3D numerical simulations of pulsar magnetospheres, revealing plasma dynamics, instabilities, and wind structures that advance understanding of pulsar wind formation.

Contribution

It introduces a novel 3D particle-in-cell model for pulsar magnetospheres, capturing plasma behavior, instabilities, and wind formation in unprecedented detail.

Findings

Aligned rotators exhibit a stable disk-dome structure that is unstable to diocotron instability.

Oblique rotators form spiral striped winds with variable properties across latitudes.

Wind acceleration and magnetization depend on stellar latitude and plasma injection conditions.

Abstract

We present initial results of the first self-consistent numerical model of the outer magnetosphere of a pulsar. By using the relativistic ``particle-in-cell'' method with special boundary conditions to represent plasma dynamics in 3D, we are able to follow magnetospheric plasma through the light cylinder into the wind zone for arbitrary magnetic inclination angles. For aligned rotators we confirm the ``disk-dome'' charge-separated structure of the magnetosphere and find that this configuration is unstable to a 3D nonaxisymmetric diocotron instability. This instability allows plasma to move across the field lines and approach the corotating Goldreich-Julian solution within several rotation periods. For oblique rotators formation of the spiral ``striped wind'' in the equatorial direction is demonstrated and the acceleration of the wind and its magnetization is discussed. We find that the wind properties vary with stellar latitude; however, whether injection conditions at the pulsar are responsible for the observed jet-equator geometry of Crab and Vela is currently under investigation. We also comment on the electrodynamics of the simulated magnetospheres, their current closure, and future simulations.