  The Poynting-Robertson Cosmic Battery proposes that the innermost part of the
accretion disk around a black hole is threaded by a large scale dipolar
magnetic field generated in situ, and that the return part of the field
diffuses outward through the accretion disk. This is different from the
scenario that the field originates at large distances and is carried inward by
the accretion flow. In view of the importance of large scale magnetic fields in
regulating the processes of accretion and outflows, we study the stability of
the inner edge of a magnetized disk in general relativity when the distribution
of the magnetic field is the one predicted by the Poynting-Robertson Cosmic
Battery. We found that as the field grows, the inner edge of the disk gradually
moves outward. In a fast spinning black hole with a>0.8M the inner edge moves
back in towards the black hole horizon as the field grows beyond some threshold
value. In all cases, the inner part of the disk undergoes a dramatic structural
change as the field approaches equipartition.
