The Wu-Yang fiber bundle approach to magnetic charge has an overlooked feature -- a disk-like sheet current density and associated magnetic field in the overlap region between the Northern hemisphere and Southern hemisphere, where the different vector potentials connect. This disk magnetic field plays a role similar to the Dirac string in the Dirac approach to magnetic charge - it brings an inward magnetic flux of $4 \pi g$ which then gives rise to an outward flux of $4 \pi g$ from the Coulomb magnetic field. As with the Dirac string approach we show that placing an electric charge near this disk magnetic field gives rise to a non-zero electromagnetic field momentum. Thus the Wu-Yang approach is seen to be a Coulomb magnetic field plus a disk magnetic field, in a manner similar to the Dirac approach which has a Coulomb magnetic field plus a string magnetic field. We discuss some of the possible consequences of this. We conclude by showing that the non-singular, but non-single valued Banderet monopole potential also has a disk-like singularity and non-zero electromagnetic field momentum in the presence of an electric charge.
Comment: 16 pages, 3 figures, revtex-4. Changes in text and figures to apply the method proposed by Wu and Yang in connecting the contour across the equator. Also added discussion on the Banderet monopole potential showing another example of disk-like source and field momentum