Bochum 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
P: Fachverband Plasmaphysik
P 12: Helmholtz Graduate School for Plasma Physics I
P 12.1: Fachvortrag
Dienstag, 3. März 2015, 14:00–14:25, HZO 50
3D structure of large dust clouds in dusty plasmas — •Carsten Killer and André Melzer — Insitut für Physik, Ernst-Moritz-Arndt-Universität Greifswald
Dust clouds which fill almost the entire discharge volume can be confined in capacitively coupled radio frequency plasmas. In contrast to many dusty plasma experiments with finite dust clouds, which are studied by observing individual particles, our large dust clouds consist of about 106 particles, requiring a more global experimental approach.
In order to investigate the global properties of such a cloud, a plasma chamber with a 360∘ optical access has been constructed. The 3D dust density distribution is obtained by a computer tomography-like technique, where the line-of-sight integrated light extinction (due to scattering and absorption by the dust particles) is measured from many different angles.
Furthermore, the dust size distribution is investigated with a spatially resolving Mie Imaging technique, which is able to determine the dust size very precisely. The high resolution is achieved by measuring the angle-resolved Mie scattering intensities of illuminated particles over a wide angular range. Using the Mie Imaging technique, interesting effect such as the self-organized de-mixing of slightly differently sized dust particles or variations of the dust size over time (due to dust-plasma interaction) are investigated.