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P: Fachverband Plasmaphysik
P 14: Poster: Komplexe und Staubige Plasmen
P 14.6: Poster
Donnerstag, 28. Februar 2013, 14:00–16:00, Poster EG
Mie Scattering by a Charged Dielectric Particle – Proposal of a Novel Plasma Probe — Rafael Leslie Heinisch, •Franz Xaver Bronold, and Holger Fehske — Institut für Physik, Universität Greifswald
We study the scattering of light by a negatively charged dielectric particle. Surplus electrons affect the polarisability of the particle by their phonon-limited conductivity, either in a surface layer (negative electron affinity) or the conduction band (positive electron affinity). For particles allowing for anomalous light scattering, for instance MgO, LiF or Al2O3, we show that surplus electrons shift an extinction resonance in the infrared. While Mie scattering is routinely used as a particle size diagnostic, the particle charge has not yet been determined from the Mie signal. For dusty plasmas an optical measurement of it would be very attractive because established methods for measuring the particle charge require the plasma parameters that are not precisely known whereas Mie scattering does not. Moreover particles showing the effect could be used as minimally invasive electric probes. Determining their charge from Mie scattering and the forces acting on them by conventional means would provide a way to extract the plasma parameters locally.