Characteristics of symmetric and anti-symmetric Hasegawa modes of surface waves in a plasma slab including collisional electrons and flowing ions

The dispersion relation for electrostatic Hasegawa surface wave propagating on the interface of a cold dusty plasma slab whose constituents are collisional electrons, collisional streaming ions and dust grains is derived. We have found that there exist high- and low-frequency branches for both symmetric and anti-symmetric modes in the plasma slab. The real frequency of the wave is found to decrease as the ion collision frequency increases for both modes. In the case of the low-frequency branch, the phase velocity of the Hasegawa surface wave in a slab is always faster (slower) than that in a semi-bounded plasma for symmetric mode (anti-symmetric mode). We also found that the Hasegawa surface waves can be damped by the collisional dissipation. However, the characteristic of damping is quite different for the two modes: the magnitude of damping rate for symmetric (anti-symmetric) mode increases (decreases) as the slab thickness decreases. (paper)