Force-Free Magnetospheres of Stars and Black Holes

Forty years after the discovery of pulsars and realization that they possess a force-free magnetosphere, their most basic observed feature---pulsed emission---has not been explained.  Our attitude is to take a step back and look at the fundamentals of the subject.  We have investigated force-free magnetospheres of stars and black holes using some techniques imported from general relativity research.  We have found non-stationary, non-axisymmetric exact solutions that should describe the outer magnetosphere of pulsars, including those that are accelerated or torqued.  This description includes the exact dynamics of the current sheet, where gamma-ray emission may originate.  For an accelerated aligned pulsar, the radiated power is enhanced relative to what would be expected for a magnetic dipole in vacuum.  Finally, we have derived the standard cartoon of the aligned pulsar magnetosphere from an explicit, minimal set of assumptions, clarifying what assumptions are actually necessary.