20 research outputs found
Kinetic approach to low-frequency waves in dusty self-gravitating plasmas - art. no. 066406.
Dust-acoustic waves in collisional dusty plasmas of planetary rings
Aims.The effects of ion and neutral drag forces on
stability of low-frequency wave modes is investigated from the
point of view of parameters relevant to the plasma environment in
the vicinity of the main Saturn rings. The electrons and ions are
considered to be magnetized and corotate with the planet, while the
dust grains are not magnetized and move around the planet on
Keplerian orbits.
Methods.The wave modes of low-frequencies in such dusty
plasma, propagating along the ring in the azimuthal direction are
analyzed based on the susceptibilities derived from the standard
fluid approach and model presentation of the drag forces valid in
the parameter regime of the dusty plasma of planetary rings.
Results.It is
found that the ion drag force can crucially change the stability of
dust-acoustic perturbations. Inside the co-rotation distance the
ion drag force can be responsible for the excitation of
dust-acoustic waves, while for the region outside the synchronous
orbit this mode can hardy be excited (at radial distances
corresponding to the main rings). The instability due to the ion
drag force could be also of some importance for perturbations in
remote rings, where the relative ion-dust velocities exceed their
thermal speed