MAGNETOSTATIC IMAGE THEORY FOR THE PERMEABLE SPHERE

The image of a electrostatic point charge in a conducting sphere, produced by Kelvin's inversion theory, has become well-known since its formulation in 1848. The corresponding image theory in terms of a point charge plus a line charge was recently developed for the dielectric sphere by one of the authors. This theory is adapted to the magnetically polarizable sphere with magnetic charges, dipoles or current loops as sources. For the current loop, the image is seen to consist of a conical surface current plus an edge line current with expressions simple enough to allow numerical computations with a pocket calculator. A recently published result for the superconducting sphere is seen to be a special case of the present theory for mu = 0.