0 v 2 2 4 Ju l 2 00 4 Pulsar Magnetosphere : A General Relativistic Treatment

Chul H. Lee and Hyun Kyu Lee Department of Physics, Hanyang University, Seoul, 133-791, KOREA Abstract A fully general relativistic description of the pulsar magnetosphere is provided. To be more concrete, a study of the pulsar magnetosphere is performed in the context of general relativistic magnetohydrodynamics (MHD) employing the so-called Grad-Shafranov approach. Not surprisingly, the resulting Grad-Shafranov equations and all the other related general relativistic MHD equations turn out to take essentially the same structures as those for the (rotating) black hole magnetosphere. Other different natures between the two cases including the structure of singular surfaces of MHD flows in each magnetosphere are essentially encoded in the different spacetime (metric) contents. In this way, the pulsar and the black hole magnetospheres can be described in an unified fashion. Particularly, the structure of poloidal currents circulating in the neutron star magnetosphere that can provide the solution to the problem of pulsar spin-down has been uncovered in the force-free case. And it turns out to be essentially the same “magnetic braking” that has been known to operate in the Blandford-Znajek model for the central engine of AGN or quasar using the black hole spin-down.