Epicyclic oscillations of charged particles in stationary solutions immersed in a magnetic field with application to the Kerr-Newman black hole

Abstract

We consider a stationary metric immersed in a uniform magnetic field and determine the general expressions for the epicyclic frequencies of charged particles. Applications to the Kerr-Newman black hole are reached of physical consequences and reveal some new effects among which are the existence of radially and vertically stable circular orbits in the region enclosed by the event horizon and the so-called "innermost" stable circular orbit (ISCO) in the plane of symmetry.