Time-Dependent of Accretion Flow with Toroidal Magnetic Field

Abstract

In the present study time evolution of quasi-spherical polytropic accretion flow with toroidal magnetic field is investigated. The study especially focused the astrophysically important case in which the adiabatic exponent $\gamma =5/3$. In this scenario, it was assumed that the angular momentum transport is due to viscous turbulence and used $\alpha$-prescription for kinematic coefficient of viscosity. The equations of accretion flow are solved in a simplified one-dimensional model that neglects the latitudinal dependence of the flow. In order to solve the integrated equations which govern the dynamical behavior of the accretion flow, self-similar solution was used. The solution provides some insight into the dynamics of quasi-spherical accretion flow and avoids many of the strictures of the steady self-similar solution. The effect of the toroidal magnetic field is considered with additional variable $\beta [=p_{mag}/p_{gas}]$, where $p_{mag}$ and $p_{gas}$ are the magnetic and gas pressure, respectively. The solution indicates a transonic point in the accretion flow, that this point approaches to central object by adding strength of the magnetic field. Also, by adding strength of the magnetic field, the radial-thickness of the disk decreases and the disk compresses. It was analytically indicated that the radial velocity is only a function of Alfv'en velocity. The model implies that the flow has differential rotation and is sub-Keplerian at all radii.

6 pages, 2 figures, accepted by MNRAS

References in corpus (5)

• Accretion disc viscosity: how big is alpha?
• Accretion Discs with Strong Toroidal Magnetic Fields
• Self-Similar Solutions for ADAF with Toroidal Magnetic Fields
• Transport of toroidal magnetic field by the meridional flow at the base of the solar convection zone
• Self-Similar Solutions of Viscous-Resistive ADAFs With Poloidal Magnetic Fields

Cited by in corpus (8)

• Dynamics of Hot Accretion Flow with Thermal Conduction
• Time Dependence of Advection Dominated Accretion Flow with a Toroidal Magnetic Field
• Viscous and resistive accretion flows with radially self-similar and outflows
• Standing shocks in magnetized advection accretion flows onto a rotating black hole
• Self-similar solutions of viscous and resistive ADAFs with thermal conduction
• Anchoring polar magnetic field in a stationary thick accretion disk
• Self-similar Evolutionary Solutions for Accreting Magneto-fluid around a Compact Object with Finite Electrical Conductivity
• Self-Similar Solutions for Viscous and Resistive ADAF