Electromagnetic streaming instabilities of magnetized accretion disks
  with strong collisional coupling of species
  Electromagnetic streaming instabilities of multicomponent collisional
magnetized accretion disks are studied. Sufficiently ionized regions of the
disk are explored where there is strong collisional coupling of neutral atoms
with both ions and dust grains simultaneously. The steady state is investigated
in detail and the azimuthal and radial background velocities of species are
calculated. The azimuthal velocity of ions, dust grains, and neutrals is found
to be less than the Keplerian velocity. The radial velocity of neutrals and
dust grains is shown to be directed inward of the disk. The general solution
for the perturbed velocities of species taking into account collisions and
thermal pressure is obtained. The effect on the collisional frequencies, due to
density perturbations of charged species and neutrals, is included. It is shown
that dust grains can be involved in the fast electromagnetic perturbations
induced by the ions and electrons through the strong collisions of these grains
with neutrals that in turn have a strong collisional coupling with the ions.
The dispersion relation for the vertical perturbations is derived and its
unstable solutions due to different background velocities of ions and electrons
are found. The growth rates of the streaming instabilities considered can be
much larger than the Keplerian frequency.
