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P: Plasmaphysik

P 11: Dusty Plasmas and Low Temperature Discharges (Poster Session)

P 11.3: Poster

Thursday, April 5, 2001, 12:30–15:00, AT2

On the interaction between plasma and micro-disperse powder particles in different gases — •Holger Kersten, Philipp Latychev, Gabi Thieme, and Rainer Hippler — Institute for Physics, University Greifswald, Domstrasse 10a, D-17487 Greifswald

The spatial distribution of dust particles in a low-temperature plasma is a consequence of several forces acting on the particles. In the experiments the distribution of SiO2 particles above the rf-electrode has been studied for different gases (He, Ne, Ar, H2, N2, O2). Particle size, discharge power and pressure have been varied.

The height of the particle cloud above the electrode decreases with increasing gas pressure. The distance is remarkably larger for light gases (H2, He) compared to the havier gases (O2, Ar). The ratio between particle height and atomic mass of the gas is kind of a similarity parameter. The smaller particles always float in a higher position than the larger particles. It has been observed that the particles with smaller diameter already form a plasma crystal at a rather low pressure compared to the large particles.

The observations of the particle behaviour in dependence on the discharge parameters support the idea of using such particles as micro-probes for the sheath region of a process plasma.