Aachen PK 2003 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

P: Plasmaphysik

P 4: Poster I

P 4.37: Poster

Montag, 17. März 2003, 17:45–19:15, Foyer

Mode Spectra of Thermally Excited 2D Dust Coulomb Clusters — •Andre Melzer, Markus Klindworth, and Alexander Piel — Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität Kiel

The study of 2D finite Coulomb clusters in complex plasmas allows a detailed insight into the dynamic properties of complex plasmas. These clusters consist of a small number of microspheres (N=1… 150) trapped in the sheath of an rf discharge at low gas pressure. The particles are confined vertically in a strong potential well formed by gravity and electric field forces. Horizontally (radially) they are confined in a shallow parabolic potential. The clusters arrange in concentric rings generating a “periodic table” of 2D finite clusters. The dynamical behavior of these systems is described in terms of their normal mode oscillations. Due to the small numbers of particles involved experimental results can be compared to theory and simulations in every detail. Here, measurements on the normal modes of different 2D finite clusters are presented. The normal mode oscillations of the cluster are extracted from the thermal fluctuations of the particle positions. From a comparison with calculated normal modes, the interaction between the microspheres has been derived in terms of the particle charge and the screening strength. Also a number of special modes has been investigated and compared among different clusters.