TITLE:
Stability and Vorticity Production in Stratified Astrophysical Disks
AUTHORS:
E. S. Uchava, A. G. Tevzadze, G. D. Chagelishvili
KEYWORDS:
Accretion Disks; Protoplanetary Disks; Turbulence
JOURNAL NAME:
Journal of Modern Physics,
Vol.4 No.5B,
July
10,
2013
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.