Contopoulos, Ioannis

The force-free magnetosphere of a rotating black hole.

Author list: Ioannis Contopoulos

We present the structure of the steady-state force-free magnetosphere around a Kerr black hole. The solution depends on the distributions of the magnetic field angular velocity and the poloidal electric current. These are not arbitrary. They are determined self-consistently by requiring that magnetic field lines cross smoothly the two singular surfaces of the problem, the inner `light surface' located inside the ergosphere, and the outer `light surface' which is the generalization of the pulsar light cylinder. We obtain the rate of electromagnetic extraction of energy and confirm the results of Blandford & Znajek (1977). Unless the black hole is surrounded by a thick disk and/or extended disk outflows, the asymptotic solution is very similar to the asymptotic pulsar magnetosphere which has no collimation and no significant plasma acceleration.