Linearly polarized superluminal waves in pulsar winds

TL;DR

This paper explores the transition of pulsar winds from striped magnetohydrodynamic waves to superluminal electromagnetic waves, highlighting their role in energy conversion processes before the wind reaches the termination shock.

Contribution

It introduces the concept of linearly polarized superluminal waves in pulsar winds and discusses their significance in energy conversion mechanisms.

Findings

Superluminal waves can propagate when plasma density drops below a critical level.

Conversion of striped wind into superluminal waves occurs before the termination shock.

Superluminal waves play a key role in converting Poynting flux to kinetic energy.

Abstract

Pulsar winds are the ideal environment for the study of non-linear electromagnetic waves. It is generally thought that a pulsar launches a striped wind, a magnetohydrodynamic entropy wave, where plasma sheets carried along with the flow separate regions of alternating magnetic field. But when the density drops below a critical value, or equivalently for distances from the pulsar greater than a critical radius, a strong superluminal wave can also propagate. In this contribution we discuss the conversion of the equatorial striped wind into a linearly polarized superluminal wave, and we argue that this mode is important for the conversion of Poynting flux to kinetic energy flux before the outflow reaches the termination shock.