Self-similar structure of magnetized ADAFs and CDAFs
Abstract
(Abridged) We study the effects of a global magnetic field on viscously-rotating and vertically-integrated accretion disks around compact objects using a self-similar treatment. We extend Akizuki & Fukue's work (2006) by discussing a general magnetic field with three components () in advection-dominated accretion flows (ADAFs). We also investigate the effects of a global magnetic field on flows with convection. For these purposes, we first adopt a simple form of the kinematic viscosity to study magnetized ADAFs. Then we consider a more realistic model of the kinematic viscosity , which makes the infall velocity increase but the sound speed and toroidal velocity decrease. We next use two methods to study magnetized flows with convection, i.e., we take the convective coefficient as a free parameter to discuss the effects of convection for simplicity. We establish the relation for magnetized flows using the mixing-length theory and compare this relation with the non-magnetized case. If is set as a free parameter, then and increase for a large toroidal magnetic field, while decreases but increases (or decreases) for a strong and dominated radial (or vertical) magnetic field with increasing . In addition, the magnetic field makes the relation be distinct from that of non-magnetized flows, and allows the or structure for magnetized non-accreting convection-dominated accretion flows with (where is the parameter to determine the condition of convective angular momentum transport).
Keywords
Cite
@article{arxiv.0805.3254,
title = {Self-similar structure of magnetized ADAFs and CDAFs},
author = {Dong Zhang and Z. G. Dai},
journal= {arXiv preprint arXiv:0805.3254},
year = {2015}
}
Comments
22 pages, 5 figures, Accepted for publication in MNRAS