Effect of pseudo collisions on plasma diagnostics

This paper presents basic interrelations between low-pressure plasmas and an optimized probe, based on active plasma resonance spectroscopy. Special attention is paid to the determination of the collision frequency, which can be separated into two types: the collision frequency of the momentum between electrons and neutral particles and the pseudo collision frequency, which describes the deflection of electrons by an electromagnetic field of an inserted probe. Based on the multipole resonance probe (MRP) and in-situ reflection measurements a specific resonance behaviour can be evaluated. The electron density can be calculated via the resonance frequency and the collision frequency can be calculated via the width of the corresponding resonance peak. 3D electromagnetic field simulations and measurements in an argon-oxygen plasma confirm the suitability of the presented simultaneous evaluation of all critical parameters.