Ion trajectories calculation for negatively biased needle cathode in volume discharge plasma

Ion trajectories were simulated for the case of multi-needle negatively biased electrode immerged into the volume type plasma. The model was simplified to the 2d case with planar plasma boundary. The electrical field distribution was calculated with the FEA method. Resulting piece wise function was then used to predict ion trajectories emitted from the plasma sheath boundary. Series of the ion trajectories were simulated for different plasma and accelerating gap parameters using single particle analysis. Distribution of the ion current density along the needle surface and angles of the ion incidence were obtained from the simulation. Experimental and theoretical etching profiles are consistent