A particle-in-cell/Monte Carlo model of the Ar⁺ ion collection in He gas by a cylindrical Langmuir probe in the transition regime

Dipartimento di Chimica dell'Università and IMIP-CNR, sect. Bari, via Orabona 4, 70126 Bari, Italy

Corresponding author: cscpft61@area.ba.cnr.it

Received: 17 May 2002
Revised: 20 December 2002
Accepted: 20 December 2002
Published online: 25 February 2003

Abstract

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.