Corotation and Poloidal Flow in Pulsar Magnetospheres

Abstract

In recent years, authors have recognized that it is essential to allow for the non-corotational part - '\l(/J of the electric field in pulsar magneto spheres, but have continued to neglect it .in zones of corotation. It is shown here that, in order to understand the flow dynamics and avoid absurdities, it is essential to use the correct functional form for (/J everywhere outside the star-without exception. Implications include a potential difference between zones of corotating electrons and ions, resulting in a large local 'V(/J field in vortical boundary layers separating those zones, directed so as to force a mixing of electrons and ions there. This result clashes sharply with a well-known conclusion of Holloway, based on use of the zero-inertia approximation with (/J piecewise constant on magnetic field lines: he found the electron and ion zones to be separated by evacuated regions. A further consequence of the present analysis is a possible mirroring of electrons between the northern and southern boundary layers, while they drift toward the star because of dissipative effects. These findings are not restricted to the usual axisymmetric case, but are valid for the oblique rotator, with non-aligned magnetic and rotation axes, so long as zones of corotation exist.