Numerical Simulations of Super-Eddington Accretion Flows

Abstract

In this chapter, we summarize recent progress on the properties of accretion disks when the accretion rate exceeds the so-called Eddington limit based on multi-dimensional radiation magnetohydrodynamic simulations. We first summarize the classical models that are used to describe the accretion disks in the super-Eddington regime with an emphasis on the key uncertainties in these models. Then we show that radiation-driven outflows are ubiquitously found by numerical simulations of super-Eddington accretion disks. Some key physical processes on energy transport inside the disk are also identified by numerical simulations. Radiative and mechanical output as a function of mass accretion rates, black hole mass, spin, and magnetic field topology are summarized. Applications of super-Eddington accretion disks to different astrophysical systems, particularly tidal disruption events, are also discussed.