Stability and Vorticity Production in Stratified Astrophysical Disks

E. S. Uchava, A. G. Tevzadze, G. D. Chagelishvili

1Department of Physics, Faculty of Exact and Natural Sciences, Tbilisi State University, Tbilisi, Georgia 2E. Kharadze Abastumani Astrophysical Observatory, Ilia State University, Tbilisi, Georgia 3M. Nodia Institute of Geophysics, Tbilisi State University, Tbilisi, Georgia.
Department of Physics, Faculty of Exact and Natural Sciences, Tbilisi State University, Tbilisi, Georgia.

DOI: 10.4236/jmp.2013.45B004                

Abstract

We study local linear non-axisymmetric perturbations in fully stratified 3D astrophysical disks. Radial stratification is set to be described by power law, while vertical stratification is set to be exponential. We analyze the linear perturbations in local shearing sheet frame and derive WKB dispersion equation. We show that stratification laws of the disk matter define not only the thermal stability of the disk, but also the efficiency of the potential vorticity production by rotationg convective turbulence in astrophysical disks. Taken developed convective turbulence we assume nonlinear tendencies set by linear spectrum and show that vortices are unlikely to be generated in rigid rotation flows. In contrast, differential rotation yields much higher vortex production rate that depends on the disk thickness, distance from the central object and the spectral characteristics of the developed thermal turbulence. It seems that measurements of the temperature and density distribution in accretion disks may indicate the efficiency of the turbulence development and largely define the luminosity characteristic of accreting flows.

Keywords

Accretion Disks; Protoplanetary Disks; Turbulence

Conflicts of Interest

The authors declare no conflicts of interest.

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