Superluminal waves in pulsar winds
Abstract
The energy lost by a rotation-powered pulsar is carried by a relativistic flow containing a mixture of electromagnetic fields and particles. In the inner regions, this is thought to be a magnetically dominated, cold, electron-positron wind that is well described by the MHD equations. However, beyond a critical radius r_{cr}, the same particle, energy and momentum fluxes can be transported by a strong, transverse electromagnetic wave with superluminal phase speed. We analyze the nonlinear dispersion relation of these waves for linear and circular polarization, and find the dependence of r_{cr} on the mass-loading, magnetization and luminosity of the flow, as well as on the net magnetic flux. We show that, for most isolated pulsars, the wind lies well outside r_{cr}, and speculate that superluminal modes play an important role in the dissipation of electromagnetic energy into nonthermal particles at the termination shock.
Cite
@article{arxiv.1109.2756,
title = {Superluminal waves in pulsar winds},
author = {Ioanna Arka and John G. Kirk},
journal= {arXiv preprint arXiv:1109.2756},
year = {2015}
}
Comments
Submitted to ApJ