Reduction of sheath potential and particle flux at a target plate by negatively charged dust particles

Tomita, Yukihiro*; Smirnov, R.*; Chutov, Y.*; Takayama, Arimichi*; Takizuka, Tomonori

Electrostatic potential formation due to negatively charged dust particles near a divertor plate is studied by one-dimensional kinetic analysis. It is shown that the negatively charged dust particles reduce the ion-sheath potential drop in front of the plate. Dust particles with a large radius (100 micron) reduce the potential drop significantly despite the low dust-to-plasma density ratio (10to-8). The plasma particle flux is reduced appreciably by the absorption by the dust particles.