Internal structure of a thin transonic disk

Beskin, V. S.; Tchekhovskoy, A. D.

Internal structure of a thin transonic disk

Authors

Description

The internal structure of the thin transonic disk accreting onto a nonrotating black hole inside the last stable orbit ($r < 3r_{\rm g}$) is considered within the hydrodynamical version of the Grad-Shafranov equation. It is shown that in the vicinity of the sonic surface takes place a sharp diminishing of the disk thickness. As a result, in the vertical balance equation the dynamical forces $ρ[({\bf v}\nabla){\bf v}]_θ$ become important, these on the sonic surface being of the same order as the pressure gradient $\nabla_θ P$. In the supersonic region the thickness of the disk is determined by the form of ballistic trajectories rather than by the pressure gradient.
9 pages, 1 figure, uses sc3conf.sty, to appear in Proc. Third Sakharov Conference on Physics, A.Semikhatov et al. (eds.), Scientific World, Moscow (2003)