The electrostatic sheath in an electronegative dusty plasma

Bohm criterion for the electrostatic sheath in electronegative dusty plasmas, which are composed of electrons, negative and positive ions, as well as dust grains, is investigated with Sagdeev potential, taking into account the self-consistent dust charge variation. The numerical solutions show that the dust and negative ion densities, as well as the positive ion and dust Bohm velocities, all have effects on the dust charge at the sheath edge. The positive ion and dust Bohm velocities increase with the growth of the dust density, while both of them decrease with the growth of negative ion density. Furthermore, the interactions between the two Bohm velocities are considered. The results are examined and found to be reliable by the quantitative analysis of Sagdeev potential.