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P: Fachverband Plasmaphysik

P 12: Poster II

P 12.20: Poster

Mittwoch, 22. März 2023, 17:30–19:00, HSZ EG

The sticking machine: measuring electron sticking coefficients using dusty plasmas — •Armin Mengel and Franko Greiner — Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel

A central property of (micro-)particles in laboratory plasmas is the strong negative charge they accumulate. It is, among other things, dependent on the electron sticking coefficient of the particle material. In many descriptions of plasma-surface interaction, the electron sticking coefficient is, due to lack of better knowledge, assumed to be 1. However, recent quantum-mechanical calculations^[1] hint at significantly smaller values for dielectric surfaces at low energies, while metallic surfaces are known to have a sticking coefficient very close to unity. Subsequent excitation and long-distance-microscopy measurements with SiO₂ and metal-coated particles under the same plasma conditions allow for the determination of the ratio of the particles’ charge and sticking coefficient. We present a study comparing metal-coated particles with SiO₂ particles in order to obtain the sticking coefficient of the latter. This enables us to determine the low-energy sticking coefficient of dielectric materials using dusty plasma.
[1] F.X.Bronold et al., Plasma Phys. Cont. Fusion 59 (2017) 014011,
https://iopscience.iop.org/article/10.1088/0741-3335/59/1/014011