Generating vorticity and magnetic fields in plasmas in general   relativity: spacetime curvature drive
  Using the generally covariant magnetofluid formalism for a hot plasma, a new spacetime curvature driven mechanism for generating seed vorticity/magnetic field is presented. The ``battery'' owes its origin to the interaction between gravity and the inhomogeneous plasma thermodynamics. The general relativistic drive is evaluated for two simple cases: seed formation in a simplified model of a hot plasma accreting in stable orbits around a Schwarzschild black hole, and for particles in free fall near the horizon. Some astrophysical applications are suggested. 
Felipe A. Asenjo, Swadesh M. Mahajan and Asghar Qadir
physics.plasm-ph gr-qc