Enhanced Dissipation Rate of Magnetic Field in Striped Pulsar Winds by the Effect of Turbulence

TL;DR

This study demonstrates that turbulence significantly accelerates magnetic field dissipation in pulsar wind nebulae, potentially resolving the longstanding sigma-problem by showing dissipation occurs rapidly and independently of resistivity.

Contribution

The paper introduces a new simulation and analytical model showing turbulence enhances magnetic dissipation in pulsar winds, independent of resistivity, addressing the sigma-problem.

Findings

Turbulence stretches current sheets, increasing magnetic dissipation.

Most magnetic energy dissipates within a few eddy-turnover times.

Dissipation rate is resistivity-independent in the model.

Abstract

In this letter we report on turbulent acceleration of the dissipation of magnetic field in the postshock re- gion of a Poynting flux-dominated flow, such as the Crab pulsar wind nebula. We have performed two- dimensional resistive relativistic magnetohydrodynamics simulations of subsonic turbulence driven by the Richtmyer-Meshkov instability at the shock fronts of the Poynting flux-dominated flows in pulsar winds. We find that turbulence stretches current sheets which substantially enhances the dissipation of magnetic field, and that most of the initial magnetic field energy is dissipated within a few eddy-turnover times. We also develop a simple analytical model for turbulent dissipation of magnetic field that agrees well with our simulations. The analytical model indicates that the dissipation rate does not depend on resistivity even in the small resistivity limit. Our findings can possibly alleviate the {\sigma}-problem in the Crab pulsar wind nebulae.