Modes of disc accretion onto black holes

Abstract

I review our current theoretical understanding of the different possible rotating modes of accretion onto a black hole. I discuss both thick adiabatic flows and radiatively efficient thin disc solutions. I present a new self-consistent unified analytical description of two-phase thin disc--corona systems in which magneto-rotational instability is responsible for angular momentum transport in the disc and for the corona generation. Finally, I briefly discuss the role of magnetic fields in bridging the gap between accretion discs theory and jet production mechanisms

10 pages, 1 colour figure. Latex macro sprocl.sty. Invited review, to be published in the proceedings of the 5th Italian AGN Meeting "Inflows, Outflows and Reprocessing around black holes" (2002)