Aachen PK 2003 – scientific programme

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P: Plasmaphysik

P 17: Poster III

P 17.37: Poster

Thursday, March 20, 2003, 17:30–19:15, Foyer

Impedance probe measurements in complex plasmas — •Oliver Arp, Markus Klindworth, André Melzer, and Alexander Piel — Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität Kiel, 24098 Kiel

Measurements of the electron density is an important topic in complex plasmas. Interesting investigations are related to the question of electron depletion due to the presence of dust as a consequence of particle charging.

Langmuir probe measurements in complex plasmas have been performed by IEAP, Kiel University in the laboratory and under microgravity conditions. A different method to measure the electron density is presented here to complement Langmuir probe measurements.

It is shown that the impedance probe (IP), that is commonly used for ionospheric measurements, yields reliable densities in rf-plasmas over a wide range of plasma parameters. In addition the IP avoids disadvantages of the Langmuir probe, e.g. the contamination by dust.

As an application of the IP in complex plasmas electron density measurements are performed in a trapped dust layer above an electrode of an rf-discharge. The comparison of complex plasmas and dust-free plasmas shows significant differences in the electron density that can be attributed to electron depletion.