Simulations of Ion Velocity Distribution Functions Taking into Account Both Elastic and Charge Exchange Collisions

TL;DR

This paper presents detailed Monte Carlo simulations of ion velocity distribution functions considering both elastic and charge exchange collisions, validated against experimental data, revealing complex scattering effects on IVDF anisotropy.

Contribution

It introduces a comprehensive simulation approach that accurately models IVDF considering elastic and charge exchange collisions, challenging previous simplified assumptions.

Findings

Elastic collisions significantly affect IVDF shape.

IVDF cannot be factorized into independent transverse and parallel components.

Simulation results agree with experimental ion mobility and diffusion data.

Abstract

Based on accurate representation of the He+-He angular differential scattering cross sections consisting of both elastic and charge exchange collisions, we performed detailed numerical simulations of the ion velocity distribution functions (IVDF) by Monte Carlo collision method (MCC). The results of simulations are validated by comparison with the experimental data of the ion mobility and the transverse diffusion. The IVDF simulation study shows that due to significant effect of scattering in elastic collisions IVDF cannot be separated into product of two independent IVDFs in the transverse and parallel to the electric field directions.