Magnetostatic interaction energy between a point magnet and a ring magnet

We find an exact closed-form expression for the magnetostatic interaction energy between a point magnet and a ring magnet in terms of complete elliptic integrals. The exact expression for the energy exhibits an equilibrium point close to the axis of symmetry of the ring magnet. Our methodology will be useful in investigations concerning magnetic levitation, and in the study of Casimir levitation.