Universal behaviour of $\alpha$-viscosity in black hole accretion discs

Marek A. Abramowicz, Axel Brandenburg, Jiří Horák +4

The Shakura-Sunyaev $\alpha$-viscosity coefficient, defined as the ratio of total stress to total pressure, $\alpha =\mathbb{T}/p$, began to play an important role in the development of accr…