Self-Similar Accretion Flows with Convection：（自相似与对流吸积流）.pdfVIP

Self-Similar Accretion Flows with Convection Ramesh Narayan Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, U. S. A. 1 2 Igor V. Igumenshchev , Marek A. Abramowicz Institute of Theoretical Physics, Goteborg University and Chalmers University of Technology, 412 96 Goteborg, Sweden 9 9 9 1 ABSTRACT c e D We consider height-integrated equations of an advection-dominated accretion flow (ADAF), assuming that there is no mass outflow. We include convection through a mixing length for- 1 malism. We seek self-similar solutions in which the angular velocity and sound speed scale as 2 R−1/2, where R is the radius, and consider two limiting prescriptions for the transport of angular 1 momentum by convection. In one limit, the transport occurs down the angular velocity gradient, v so convection moves angular momentum outward. In the other, the transport is down the specific 9 4 angular momentum gradient, so convection moves angular momentum inward. We also consider 4 general prescriptions which lie in between the two limits. 2 When convection moves angular momentum outward, we recover the usual self-similar solution 1 for ADAFs in which the mass density scales as ρ ∝ R−3/2. When convection moves angular 9 9 momentum inward, we again find this solution if the viscosity coefficient α αcrit1 ∼ 0.05. /