The influence of large-scale magnetic field in the structure of supercritical accretion flow with outflow

Abstract

We present the effects of ordered large-scale magnetic field on the structure of supercritical accretion flow in the presence of an outflow. In the cylindrical coordinates (r, φ, z), we write the 1.5-dimensional, steady-state (⁠|$\frac{\partial }{\partial t}= 0$|⁠) and axisymmetric (⁠|$\frac{\partial }{\partial \varphi }= 0$|⁠) inflow–outflow equations by using self-similar solutions. Also, a model for radiation pressure supported accretion flow threaded by both toroidal and vertical components of magnetic field has been formulated. For studying the outflows, we adopt a radius-dependent mass accretion rate as |$\dot{M}=\dot{M}_{{\rm out}}{(\frac{r}{r_{{\rm out}}})^{s+\frac{1}{2}}}$| with |$s = \frac{1}{2}$|⁠. Also, by following the previous works, we have considered the interchange of mass, radial and angular momentum and the energy between inflow and outflow. We have found numerically that two components of magnetic field have the opposite effects on the thickness of the disc and similar effects on the radial and angular velocities of the flow. We have found that the existence of the toroidal component of magnetic field will lead to an increase in the radial and azimuthal velocities as well as the relative thickness of the disc. Moreover, in a magnetized flow, the thickness of the disc decreases with increase in the vertical component of magnetic field. The solutions indicated that the mass inflow rate and the specific energy of outflow strongly affect the advection parameter. We have shown that by increasing the two components of magnetic field, the temperature of the accretion flow decreases significantly. On the other hand, we have shown that the bolometric luminosity of the slim discs for high values of |$\dot{m} (\dot{m}>>1)$||$\dot{m}\,(\dot{m}\gg 1)$| is not sensitive to mass accretion rate and is kept constant (L ≈ 10LE).