The potential formation with dust particles near a target plate was studied by using one dimensional kinetic analysis. The dust particles in fusion devices (TEXTOR-94, ASDEX-U, LHD) have been collected and analyzed their characteristics [1, 2], where the radii are widely ranged between 10 nm and 100 μm. With the long plasma confinement in fusion plasma experiments, the effect of dust particles on potential formation near target plates should be important. Moreover in the processing plasma the dust particles play an important role due to the comparatively high density.
In order to investigate the effect of dust particles on the potential formation near a target plate, the floating target is installed at the end of the system and plasma particles are injected from the other boundary. The immovable dust are uniformly distributed inside the system. In case of sourceless of plasma particles and collisionless between plasma particles, the local energy distribution function of plasma particles is expressed by the injected one. The charge of dust is determined from the equality of plasma particle fluxes to the dust. The existence of dust particles changes potential formation near the target plate. It was clarified that dust particles reduces the sheath potential at the target plate, where the bombardment of ions with high energy to the plate is avoided. The dust density of the order 10^-6 to the plasma density with the radius of 1 μm to the plasma density effectively reduces it for the divertor plasma in fusion devices. At the threshold dust density the electric field at the wall becomes zero. As the dust density increases higher than the threshold value, the position of the maximum potential approaches to the injection position of plasma and the stationary oscillation appears inside the system. This oscillation was identified as a stationary dust ion-acoustic mode.

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