On Angular Momentum Transport in Convection-dominated Accretion Flows

Convection-dominated accretion flow (CDAF) is a promising model to explain underluminous accreting black holes in X-ray binaries and galactic nuclei. I discuss the effects of angular momentum transport in viscous hydrodynamical and MHD CDAFs. In hydrodynamical CDAFs, convection transports angular momentum inward, and this, together with the outward convection transport of thermal energy, determine the radial structure of the flow. In MHD CDAFs, convection can transport angular momentum either inward or outward, depending in the properties of turbulence in rotating magnetized plasma, which are not fully understood yet. The direction of convection angular momentum transport can affect the law of MHD CDAFs.