Equatorial Pulsar Winds

Abstract

Atraditional problem in pulsar wind physics has been the nature of the pulsar wind.Ontheoretical grounds, the wind is expected to be dominated by Poynting flux associated with the outgoing magnetic field lines anchored on the polar caps of the rotating neutron star, while observations of the Crab Nebula demonstrate that the wind must be dominated by kinetic energy before the termination shock. Here we suggest a new approach to this old problem by studying the distributed currents rather than the singular sheet currents which have been the object of study in most work.We find that, at a distance well in between the light cylinder and the termination shock, current starvation sets in, and electric fields develop along the magnetic field lines which cause the current to dissipate and convert at least half of the Poynting flux into kinetic energy flux in a relatively thin shell. In the shell, at least half of the current closes across the magnetic field lines, the pitch of the spiralling magnetic field lines jumps downward strongly, and the outer pattern of magnetic field lines slips over the inner pattern.