Self-similar solutions of viscous and resistive ADAFs with thermal conduction

TL;DR

This paper investigates how thermal conduction influences the structure of viscous, resistive ADAFs using self-similar solutions, highlighting its significance as an energy mechanism in hot accretion flows around galactic nuclei.

Contribution

It introduces a self-similar model of ADAFs incorporating variable thermal conduction, viscosity, and magnetic diffusivity, providing new insights into their combined effects on flow dynamics.

Findings

Radial velocity is highly subsonic.

Rotational velocity is sub-Keplerian and can become zero.

Thermal conduction significantly impacts energy transport in ADAFs.

Abstract

We have studied the effects of thermal conduction on the structure of viscous and resistive advection-dominated accretion flows (ADAFs). The importance of thermal conduction on hot accretion flow is confirmed by observations of hot gas that surrounds Sgr A$^*$ and a few other nearby galactic nuclei. In this research, thermal conduction is studied by a saturated form of it, as is appropriated for weakly-collisional systems. It is assumed the viscosity and the magnetic diffusivity are due to turbulence and dissipation in the flow. The viscosity also is due to angular momentum transport. Here, the magnetic diffusivity and the kinematic viscosity are not constant and vary by position and $\alpha$-prescription is used for them. The govern equations on system have been solved by the steady self-similar method. The solutions show the radial velocity is highly subsonic and the rotational velocity behaves sub-Keplerian. The rotational velocity for a specific value of the thermal conduction coefficient becomes zero. This amount of conductivity strongly depends on magnetic pressure fraction, magnetic Prandtl number, and viscosity parameter. Comparison of energy transport by thermal conduction with the other energy mechanisms implies that thermal conduction can be a significant energy mechanism in resistive and magnetized ADAFs. This property is confirmed by non-ideal magnetohydrodynamics (MHD) simulations.