Abstract
Studies of interactions between finite-size objects and plasmas are important for understanding properties of complex plasmas (i.e., plasmas containing large numbers of dust grains) or studies of meteroids or spacecrafts in space plasmas. The problem is highly nonlinear and can often be addressed only by numerical simulations.
I will present results from numerical simulations of the dust grain charging in flowing plasmas. The charge distribution, wake formation and its characteristic properties (e.g., ion focusing) will be discussed for grains with various shapes and made of different materials. The simulated grains can be charged by the collection of plasma particles as well as by photoemission due to directed radiation. It is shown that with photoemission, the interactions between two positively charged grains can be stronger than for grains charged only by the plasma currents. The simulations are carried out by the 2D particle-in-cell code with ions and electrons treated as individual particles. A short overview of the numerical method will also be given.