Electromagnetic dynamics of magnetized accretion disks with strong collisional coupling of neutrals with ions and dust grains

Abstract

The electromagnetic dynamics of multicomponent collisional magnetized accretion disks is considered. The sufficiently ionized regions of the disk are explored where there is the strong collisional coupling of neutrals with ions and dust grains simultaneously. The stationary state is investigated in detail and the azimuthal and radial velocities of species are found. It is obtained that due to collisions, neutrals, dust grains, and electrons drift inward and ions drift outward. The general solutions for the perturbed velocities of species with collisional and thermal effects are derived. The effect of perturbation of collisional frequencies due to the density perturbations of charged species and neutrals is taken into account. It is shown that the dust grains can be involved in the fast electromagnetic perturbations induced by ions and electrons via the strong collisions with neutrals having the strong collisional coupling with ions. The dispersion relations for axisymmetric perturbations are derived and unstable solutions due to different background velocities of species are found. The growth rates of the considered streaming instabilities can be much larger than the Keplerian frequency.