Non-axisymmetric instabilities in shocked accretion flows with differential rotation*
Service d'Astrophysique, CEA/DSM/DAPNIA, CEA-Saclay, 91191 Gif-sur-Yvette, France
2 Department of Physics, Xiamen University, Xiamen, Fujian 361005, PR China
Corresponding author: Wei-Min Gu, email@example.com
Accepted: 30 June 2003
The linear stability of a shocked isothermal accretion flow onto a black hole is investigated in the inviscid limit. The outer shock solution, which was previously found to be stable with respect to axisymmetric perturbations, is, however, generally unstable to non-axisymmetric ones. Eigenmodes and growth rates are obtained by numerical integration of the linearized equations. The mechanism of this instability is based on the cycle of acoustic waves between their corotation radius and the shock. It is a form of the Papaloizou-Pringle instability, modified by advection and the presence of the shock. As such it can be generalized to non isothermal shocked accretion flows. Blobs and vortices are generated by the shock as a by-product of the instability.
Key words: accretion, accretion disks / black hole physics / hydrodynamics / instabilities / shock waves
© ESO, 2003