|Author(s)||Dubrulle B1, Marie Louis1, Normand C2, Richard D1, 3, Hersant F4, 5, Zahn Jp3|
|Affiliation(s)||1 : CEA Saclay, GIT, SPEC, DRECAM,DSM,CNRS,URA 2464, F-91191 Gif Sur Yvette, France.
2 : CEA Saclay, SPHT, DSM, CNRS,URA 2306, F-91191 Gif Sur Yvette, France.
3 : Observ Paris, LUTH, F-92195 Meudon, France.
4 : Inst Theoret Astrophys, D-6900 Heidelberg, Germany.
5 : Observ Paris, LESIA, F-92195 Meudon, France.
|Source||Astronomy & Astrophysics (0004-6361) (EDP Sciences), 2005-01 , Vol. 429 , N. 1 , P. 1-13|
|WOS© Times Cited||94|
|Keyword(s)||accretion, accretion disks, hydrodynamic, instabilities, turbulence|
|Abstract||We discuss the possibility that astrophysical accretion disks are dynamically unstable to non-axisymmetric disturbances with characteristic scales much smaller than the vertical scale height. The instability is studied using three methods: one based on the energy integral, which allows the determination of a sufficient condition of stability, one using a WKB approach, which allows the determination of the necessary and sufficient condition for instability and a last one by numerical solution. This linear instability occurs in any inviscid stably stratified differential rotating fluid for rigid, stress-free or periodic boundary conditions, provided the angular velocity Omega decreases outwards with radius r. At not too small stratification, its growth rate is a fraction of Omega. The influence of viscous dissipation and thermal diffusivity on the instability is studied numerically, with emphasis on the case when d ln Omega/d ln r = - 3/2 (Keplerian case). Strong stratification and large diffusivity are found to have a stabilizing effect. The corresponding critical stratification and Reynolds number for the onset of the instability in a typical disk are derived. We propose that the spontaneous generation of these linear modes is the source of turbulence in disks, especially in weakly ionized disks.|
Dubrulle B, Marie Louis, Normand C, Richard D, Hersant F, Zahn Jp (2005). An hydrodynamic shear instability in stratified disks. Astronomy & Astrophysics, 429(1), 1-13. Publisher's official version : https://doi.org/10.1051/0004-6361:200400065 , Open Access version : https://archimer.ifremer.fr/doc/00253/36469/