Reduction of Sheath Potential and Dust Ion-Acoustic Wave by Negatively Charged Dust Particles

Formation of an electrostatic potential due to negatively charged dust particles near a target plate was studied by one-dimensional kinetic analysis. Immovable dust particles are distributed uniformly inside a system. A threshold dust density makes the electric field at the target plate zero. In case of dust density below the threshold a chargeneutral point separates into two between positions of a plasma injection and a wall. An electron sheath near the injection point changes to an ion sheath in front of the target plate through the charge-neutral point. It is clarified that the negatively charged dust particles reduce the ion-sheath potential drop from the neutral point. The stationary oscillation appears in the electrostatic potential for the dust density above the threshold. We confirmed that this oscillation is the Dust Ion-Acoustic Wave (DIAW) with a wavelength of the order of Debye length, where dust charges are effective to determine the behavior. The effective dust density to produce the oscillation is as high as 1013-14 m–3 for plasma density ~ 1018 m–3 with plasma temperature ~ 10 eV.