On the stability of magnetized accretion discs

Theory of magnetized accretion discs driving jets

In this lecture I review the theory of magnetized accretion discs driving jets, with a focus on Young Stellar Objects (YSOs). I first introduce observational and theoretical arguments in favor of the “disc wind” paradigm. There, accretion and ejection are interdependent, requiring therefore to revisit the standard picture of accretion discs. A simple magnetostatic approach is shown to already p...

On the thermal stability of transonic accretion discs

Nonlinear time-dependent calculations have been carried out in order to study the evolution of the thermal instability for vertically integrated, non self-gravitating models of optically thick, transonic, slim accretion discs around black holes. In these calculations we investigated only the original version of the slim disc model with low viscosity (α = 0.001) and for a stellar mass (10M⊙) bla...

On the Stability of Elliptical Vortices in Accretion Discs

Context. The existence of large-scale and long-lived 2D vortices in accretion discs has been debated for more than a decade. They appear spontaneously in several 2D disc simulations and they are known to accelerate planetesimal formation through a dust trapping process. In some cases, these vortices may even lead to an efficient way to transport angular momentum in protoplanetary discs when MHD...

The study of Hydrodynamical wind on the observational properties of magnetized accretion flow with thermal conduction

Polarization from magnetized accretion discs: II. The effects of absorption opacity on Faraday rotation

Equipartition magnetic fields can dramatically affect the polarization of radiation emerging from accretion disk atmospheres in active galactic nuclei. We extend our previous work on this subject by exploring the interaction between Faraday rotation and absorption opacity in local, plane-parallel atmospheres with parameters appropriate for accretion discs. Faraday rotation in pure scattering at...