Published online by Cambridge University Press: 04 August 2017
Accretion disk electrodynamic phenomenae are separable into two classes: 1) disks and coronae with turbulent magnetic fields; 2) disks and black holes which are connected to a large-scale external magnetic field. Turbulent fields may originate in an α - ω dynamo, provide anomalous viscous transport, and sustain an active corona by magnetic buoyancy. The large-scale field can extract energy and angular momentum from the disk and black hole, and be dynamically configured into a collimated relativistic jet.