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

摘要

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