Linearly polarized superluminal waves in pulsar winds
  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. 
Ioanna Arka and John G. Kirk
astro-ph.HE