%0 Journal Article
%T Alpha-viscosity effects in slender tori
%A Jiri Horak
%A Marek Abramowicz
%A Lina Levin
%A Rikard Slapak
%A Odele Straub
%J Physics
%D 2012
%I arXiv
%R 10.1093/pasj/64.4.76
%X We explore effects of the Shakura-Sunyaev alpha-viscosity on the dynamics and oscillations of slender tori. We start with a slow secular evolution of the torus. We show that the angular-momentum profile approaches the Keplerian one on the timescale longer than a dynamical one by a factor of the order of 1/\alpha. Then we focus our attention on the oscillations of the torus. We discuss effects of various angular momentum distributions. Using a perturbation theory, we have found a rather general result that the high-order acoustic modes are damped by the viscosity, while the high-order inertial modes are enhanced. We calculate a viscous growth rates for the lowest-order modes and show that already lowest-order inertial mode is unstable for less steep angular momentum profiles or very close to the central gravitating object.
%U http://arxiv.org/abs/1201.5479v1