Influence of grid on the extraction characteristics of different charged ions in mixed ion beams

The extraction characteristics of multi-charged ions produced by ion sources are important for some useful applications. In this paper, the extraction process of Cu⁺, Cu²⁺, Cu³⁺, and Cu⁴⁺ mixed ions is simulated by setting ideal physical parameters in a two-dimensional particle-in-cell (PIC) code, and the evolution characteristics of density and velocity distributions of different charged ions during plasma (density about 10¹⁵ m⁻³) motion and extraction are presented. Besides, the effects of grid thickness and grid aperture on the motion behavior of different charged ions and the extracted ion current are analyzed. The results showed that the ion diffusion increases with the increase of the ion charge, and higher charged ions are more likely to be affected by the grid. This provides support for further understanding of the extraction characteristics of multi-charged mixed ion beams.