Magnetohydrodynamic Numerical Simulation of the Outflows Driven by Magnetic Field and Radiation Force from the Corona above a Thin Disk

Abstract

A hot corona is suggested to be above the standard thin disk. The anisotropy of hard X-ray emission in radio-quiet active galactic nuclei implies that the corona is not static and probably moves outwards like winds. We perform two-dimensional magnetohydrodynamical simulations to study the outflowing corona driven by magnetic field and radiation force. In our simulations, as the initial state and the boundary condition at the disk surface, the corona temperature is set to $10^9$ K inside 10 Schwarzschild radius ($r_{\rm s}$) while the corona temperature is set to $10^7$ K a 10 $r_{\rm s}$. We employ a weak poloidal magnetic field as the initial magnetic field. A collimated outflow and a wide-angle ordered outflow are observed in our simulations. The collimated outflow is around the rotational axis and has a bulk velocity of $\sim$0.03--0.3 $c$ ( $c$ is speed of light) at 90 $r_{\rm s}$, while their mass outflow rate is very low. The collimated outflow is a weak jet. The wide-angle ordered outflow is distributed at the middle and high latitudes and moves outwards with a velocity of $10^2$--$10^4$ km s$^{-1}$. The outflow velocity depends on the disk luminosity. The gas around the disk surface is turbulent, especially outside of 10 $r_{\rm s}$. The other properties of outflows are discussed in detail.