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arXiv · 1201.5479

Alpha-viscosity effects in slender tori

Jiri Horak·Marek Abramowicz·Lina Levin·Rikard Slapak·Odele Straub
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Abstract

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/α. 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.

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Jiri Horak, Marek Abramowicz, Lina Levin, Rikard Slapak, Odele Straub. 2012-01-26. Alpha-viscosity effects in slender tori. https://doi.org/10.1093/pasj%2F64.4.76

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