Kiel 2004 – scientific programme

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P: Plasmaphysik

P 10: Postersitzung: Niedertemperaturplasmen Plasmatechnologie II, Staubige Plasmen II, Magnetischer Einschluss II

P 10.24: Poster

Tuesday, March 9, 2004, 17:45–19:30, Foyer

Dynamic Properties of Finite Coulomb Clusters in Colloidal Plasmas — •Ryuta Ichiki^1,2, Yuriy Ivanov¹, and Andre Melzer¹ — ¹Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald — ²Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan

Finite Clusters in colloidal plasmas consist of a small number of microspheres (N=1… 200) trapped in the sheath of a discharge plasma. The particles acquire high negative charges and interact via their Coulomb repulsion. They are confined by strong vertical and weak horizontal (radial) potential wells, thus forming 2D concentric structures. The particles are illuminated by lasers and are observed with video cameras. The dynamic properties of these Coulomb clusters are described by their normal modes. Here, we present experiments on finite clusters in our new plasma chamber that was recently set up in Greifswald. In these experiments, the mode properties of finite Coulomb clusters have been determined for different particle numbers N. One of our goals is to relate the dynamic properties of these finite systems to the dispersion relation of waves in infinite systems. As a more technical problem, the influence of the video frame rate on the analysis of the dynamic properties is also investigated.