Orbits through the ergosphere of a Kerr black hole
Based on Carter's discovery of a constant of motion Q (in addition to energy E and angular momentum L), many authors investigated geodesic orbits in the Kerr field. In order to calculate the energy which can maximally be extracted by the Penrose process, this paper looks for the relative positions of orbits with respect to the ergosphere. Eight classes are distinguished (whether orbits reach the centre, inner horizon, ergosphere, outer region or not). The classification (orbits characterized by E and L) is done for zero energy orbits (projected on the meridian plane) and for arbitrary orbits on the equatorial plane. The results are given by sometimes complicated (in)equalities for E and L as well as in diagrams.
scientific article; zbMATH DE number 3850048