ROLE OF FINITE INERTIA AND RESISTIVITY IN AXISYMMETRIC PULSAR MAGNETOSPHERES

Inertial and resistive effects in axisymmetric pulsar magnetospheres are examined as a function of the plasma density . In the quasineutral limit the behaviour of the centrifugal-magnetic wind is consistent with torque-free formulations of the magnetic structure, the plasma inertia remaining small throughout the open field region. However, an anomalous resistivity, implying non-vanishing poloidal flow, must be invoked to prevent the two charge species from separating in the star's gravity field; unless the closed field region is charge separated, then, enhanced diffusion across field lines would be required in the vicinity of the equatorial plane. In a steady, charge-separated magnetosphere, the effect of particle inertia and/or radiation reaction must be included, at least near the light cylinder, in the momentum equation and/or its divergence (i.e. the charge density), in order to satisfy charge conservation. If the near field is dipole-like and inertial effects are reasonably small near the star surface, the equatorial charge species will be restricted to toroidal motion, and either (a) the polar charge species are also so confined, or (b) the polar particles circulate back to the star. These possibilities are discussed in the light of various integrals of the motion. © Royal Astronomical Society.