A Particle-in-Cell/Monte Carlo Model of the Ar+ Ion Collection in He Gas by a Cylindrical langmuir Probe in the Transition Regime

This article presents a particle-in-cell (PIC)/test-particle Monte Carlo (TPMC) simulation of the dynamics of Ar+ ions in the region (sheath and presheath) surrounding an attracting cylindrical Langmuir probe at medium He buffer gas pressure. The numerical model is based on a combination of PIC simulation for the ion component and fluid description for the electrons using the Boltzmann relation. The electric field is self-consistently computed via the Poisson equation. The neutrals are modeled directly by an analytical method. The elastic collisions between Ar+ ions and He atoms are accounted for using a TPMC method based on the polarization potential theory. The results of the present simulation are compared with measurements, with other probe theories and the results of other authors simulations.