Bonn 2000 – scientific programme

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P: Plasmaphysik

P 17: Staubige Plasmen (Poster)

P 17.2: Poster

Wednesday, April 5, 2000, 10:30–13:00, Aula

Nonlinear resonances in plasma crystals — •C. Zafiu, A. Melzer, and A. Piel — Institut f"ur Experimentelle und Angewandte Physik, Christian-Albrechts-Universit"at Kiel, 24098 Kiel, Germany

The crucial parameter of the properties of dusty plasmas is the charge of the individual dust particles. In typical experiments, micrometer sized particles are trapped in the space charge sheath above the lower electrode of a parallel plate rf discharge, where the electric field force levitates the charged particles against gravity. Since the electric field increases almost linearly with distance in the sheath the particles are trapped in

a harmonic potential well. In the standard charge measurement technique [1] the resonance curve of such a trapped particle in the potential well was

measured by exciting vertical oscillations due to low-frequency modulation of the rf voltage or by laser radiation pressure. Here, we present experiments on nonlinear and anharmonic effects of the vertical dust particle oscillations. The relation of these nonlinearities to anharmonicites in the potential and dust charge variations is discussed.

[1] T. Trottenberg, A. Melzer, A. Piel, Plasma Sources Sci. Technol. 4 450 (1995)