Two-dimensional Inflow-Wind Solution of Hot Accretion Flow. I. Hydrodynamics

TL;DR

This paper presents a two-dimensional hydrodynamic model of hot accretion flows incorporating thermal conduction, revealing stable convective structures and wind properties consistent with numerical simulations, advancing understanding of low accretion rate systems.

Contribution

It introduces a steady-state, axisymmetric 2D hydrodynamic solution including thermal conduction, providing new insights into wind mechanisms and stability in hot accretion flows.

Findings

Thermal conduction is essential for inflow-wind structure analysis.

The accretion flow is convectively stable with thermal conduction.

Wind properties align with previous numerical simulations.

Abstract

We solve the two-dimensional hydrodynamic equations of hot accretion flow in the presence of the thermal conduction. The flow is assumed to be in steady-state and axisymmetric, and self-similar approximation is adopted in the radial direction. In this hydrodynamic study, we consider the viscous stress tensor to mimic the effects of the magnetorotational instability for driving angular momentum. We impose the physical boundary conditions at both the rotation axis and the equatorial plane and obtain the solutions in the full $ r-\theta $ space. We have found that thermal conduction is indispensable term for investigating the inflow-wind structure of the hot accretion flows with very low mass accretion rates. One of the most interesting results here is that the disc is convectively stable in hot accretion mode and in the presence of the thermal conduction. Furthermore, the properties of wind and also its driving mechanisms are studied. Our analytical results are consistent with previous numerical simulations of hot accretion flow.