Magnetically induced confinement near a Kerr black hole

We study the orbital behaviour of a magnetized particle in the dipole magnetic field generated by a toroidal current loop around a Kerr black hole. Specifically, the modifications of the orbits in the zone between the hole and the loop are evaluated, and comparison with the pure Kerr case is made. The presence of the magnetic field gives rise to potential wells where the magnetized particle can be trapped; as a result, new stable states are allowed, even very near the hole. Worth remarking on is, in particular, the possibility of obtaining in the ergosphere stable circular orbits with total negative energy, a possibility which is geodesically forbidden.