Dynamics of an ensemble of clumps embedded in a magnetized ADAF

TL;DR

This paper analyzes how a global magnetic field influences the motion of clumps in a magnetized advection-dominated accretion flow, revealing that magnetic field strength and configuration significantly affect clump dynamics.

Contribution

It provides an analytical study of clump velocity dispersion in magnetized ADAFs, considering different magnetic field geometries and flow advection levels, which was not previously explored.

Findings

Radial velocity dispersion of clumps increases with magnetic field strength.

Purely toroidal magnetic fields reduce clump velocity dispersion near the center.

Higher advection enhances the influence of magnetic fields on clump dynamics.

Abstract

We investigate effects of a global magnetic field on the dynamics of an ensemble of clumps within a magnetized advection-dominated accretion flow by neglecting interactions between the clumps and then solving the collisionless Boltzman equation. In the strong-coupling limit, in which the averaged radial and the rotational velocities of the clumps follow the ADAF dynamics, the averaged radial velocity square of the clumps is calculated analytically for different magnetic field configurations. The value of the averaged radial velocity square of the clumps increases with increasing the strength of the radial or vertical components of the magnetic field. But a purely toroidal magnetic field geometry leads to a reduction of the value of the averaged radial velocity square of the clumps at the inner parts with increasing the strength of this component. Moreover, dynamics of the clumps strongly depends on the amount of the advected energy so that the value of the averaged radial velocity square of the clumps increases in the presence of a global magnetic field as the flow becomes more advective.