  We investigate the dynamics of radiation in an astrophysical accretion disk
around a Kerr black hole. The source of the radiation is the accretion disk
itself, and not a central object as in previous studies of the
Poynting-Robertson effect. We generate numerical sky maps from photon
trajectories that originate on the surface of the disk as seen from the inner
edge of the disk at the position of the innermost stable circular orbit (ISCO).
We investigate several accretion disk morphologies with a Shakura-Sunyaev
surface temperature distribution. Finally, we calculate the electromotive
source of the Cosmic Battery mechanism around the inner edge of the accretion
disk and obtain characteristic timescales for the generation of astrophysical
magnetic fields.
