Kiel 2011 – scientific programme

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P: Fachverband Plasmaphysik

P 8: Poster: Staubige Plasmen: Experiment und Diagnostik

P 8.14: Poster

Tuesday, March 29, 2011, 17:00–19:00, Foyer

Manipulation of the particle distribution via the Electrical Asymmetry Effect — •Edmund Schüngel, Shinya Iwashita, Dirk Luggenhölscher, and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, Ruhr-University Bochum

Recent investigations have shown that the symmetry of a capacitively coupled radio frequency discharge can be controlled by applying a fundamental frequency and its second harmonic with a fixed, but adjustable phase angle θ between the harmonics. In such electrically asymmetric discharges, the spatial potential profile changes with θ. Therefore, it is possible to manipulate the distribution of particles within the discharge by tuning the phase angle. We report first experimental results of this method using SiO₂ particles in the size range of fifty nm up to several µm, which are inserted into an argon discharge operated at low pressures. Applying laser light, the distribution of the scattering of particles between the parallel electrodes is detected by an ICCD camera. Two basic manipulation principles are investigated: In the case of changing θ slowly, the particles are always observed in a stationary state. On the contrary, a phase kick, e.g. Δ θ = 90^∘, leads to a sudden change of the discharge symmetry and, correspondingly, of the potential profile. Thus, a temporal modulation of the particle distribution is observed.