You'll find in this page my PhD (in French), defended in June 2007 on instabilities and local sources of turbulence in accretion discs. You are free to print it, but please ask me if you need one of the figures or table for your own use.


Angular momentum transport in accretion disks has been a highly controversial debate for 30 years now. We present here a study of this transport, considering some instabilities that can leads to developed turbulence in disks. The first instability considered is the subcritical hydrodynamic instability. Our numerical study shows that, although not directly observed in simulations, this instability should lead to a very weak turbulent transport, and is probably not relevant to explain disks observations. We then concider the stratorotational instability, and we show using an analytical approach that it requires very specific boundary conditions, which prevent this instability from appearing in disks. Finally, we study the magnetorotational instability, including non ideal MHD effect (resistivity and viscosity). We show numerically that these effects, although small compared to ideal MHD terms, can have a strong impact on the turbulence efficiency. This point emphasizes the role of microphysic effects in the saturation process, and the necessity to modelize these phenomena to get a self-consistant accretion disk transport model.


Full text (7.1 MB)
Table of contents and acknowledgments (396 KB)
Introduction (1.4 MB) pp 3-25
Numerical methods (2.3 MB) pp 29-71
Subcritical hydrodynamic instability (2.9 MB) pp 75-119
Stratorotational instability (1.7 MB) pp 124-142
Magnetorotational instability (2.5 MB) pp 145-176
Conclusions and appendix (2.1 MB) pp 179-229
Bibliography and summary (168 KB) pp 233-240