2D Particle-in-Cell Simulation of Varying Conditions Affecting Self-Consistent Ion Beam Extraction in a Cross-Field Plasma Source

A cross-field ion source is a device that generates and extracts ions in a structure where electric and magnetic fields are arranged perpendicular to each other, and is a system that implements efficient ion generation and beam extraction using ExB effect. In this system, the quality of an ion beam—its divergence, energy spread, and current density— is fundamentally determined by the physical conditions at the source [1]. In this study, we perform 2D electrostatic Particle-in-Cell (PIC) simulations to investigate how neutral pressure and magnetic field affect ion beam formation in an E×B plasma source. Using a ghost-grid boundary method [2] to represent the cylindrical geometry of the plasma region accurately, we simulate the emergence of a self-consistent ion flow from the source without injecting external particles. In a structure where half of a cylindrical structure is cut off, a slit is made on the surface, and a cathode is installed outside the source area to extract ions in an outward direction. Here, various conditions, such as the size of the slit, the length of slit, and the number of electrodes, are used to simulate the phenomenon of ion extraction. We focus on measuring fundamental beam parameters—beam divergence, spatial profile, current density, space-charge potential structure, and energy spread—under varying plasma conditions. The results can provide a framework for linking source plasma behavior to early-stage beam dynamics in compact ion sources.