Abstract We investigate the effects of a global magnetic field on the dynamics of an ensemble of clumps within a magnetized advection-dominated accretion flow by ignoring interactions between the clumps and then solving the collisionless Boltzman equation. In the strong-coupling limit, in which the averaged radial and rotational velocities of the clumps follow dynamics described by an Advection-Dominated Accretion Flow (ADAF), the root mean square radial velocity of the clumps is calculated analytically for different magnetic field configurations. The value of the root mean square radial velocity of the clumps increases by increasing the strength of the radial or vertical components of the magnetic field, but a purely toroidal magnetic field geometry leads to a reduction in the value of the root mean square radial velocity of the clumps in the inner parts by increasing the strength of this component. Moreover, dynamics of the clumps strongly depend on the amount of advected energy so that the value of the root mean square radial velocity of the clumps increases in the presence of a global magnetic field as the flow becomes more advective.
Keywords accretion — accretion disk — black hole physics — magnetohydrody- namics
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