Finite size effect of dust charging in the magnetized edge plasma

A newly developed 3-dimensional particle–particle particle-mesh (P3M) code is applied to study the charging process of micrometer size dust grains confined in the magnetized plasma near the material wall of a tokamak. Plasma particles (electrons and ions) are treated kinetically (particle-in-cell with Monte Carlo collisions (PIC-MCC)), which allows to self-consistently resolve the electrostatic sheath in front of the material wall. In order to accurately resolve the plasma particles’ motion close to the dust grain, the PIC technique is supplemented with molecular dynamics (MD), employing an analytic electrostatic potential for the interaction with the dust grain. The dynamics of charging of dust grains confined in the magnetized edge plasma and its dependence on the size of the dust is investigated. The results are compared with the case of unmagnetized plasma.