Experimental investigation of dissipative solitons and other self-organised patterns in dielectric barrier discharge systems
Zusammenfassung der Projektergebnisse
In this project the discharge in a laterally extended dielectric barrier discharge (DBD) system has been investigated. The discharge cell consists of two plane parallel electrodes of which at least one is covered with a dielectric layer. The gap between the electrodes is lled with a working gas (usually helium) at a pressure well below atmospheric pressure and the system is driven with an ac voltage of several hundred kilohertz. Due to the very short gas gap of less than one millimetre and the rather broad lateral extension of some centimetres, a lateral structuring of the discharge is favoured. Typical lateral patterns consist of current laments which may form a regular or irregular arrangement in the plane. Also dynamic behaviour, i. e. lateral motion of current laments is commonly observed. As all current laments are of equal size and emerge or vanish always as a whole, they can be thought as particle-like objects or, in the sense of nonlinear dynamics, as dissipative solitons. Especially interesting is the motion and the interaction of these current laments. A main diagnostic tool used in this project is the optical surface charge measurement. The surface charges on the dielectric surfaces covering the electrodes are an important feature of the DBD in general and are known to play an crucial role in laterally patterned discharges. The surface charge measurement system has been essentially rened in the course of this project with respect to temporal resolution and sensitivity. Investigating the surface charge images corresponding to the structured discharges, an unexpected internal structure of the current laments has been found. In the negative surface charge image, an additional ring of charge surrounds the core charge of the lament, which is a novelty in the physics of DBD. Furthermore it could be observed that during the interaction of two current laments an intermediate bound state of the laments occurs which is dened by a distinct distance that the laments keep for several ten milliseconds. Finally it could be showed that the distance dening the intermediate state coincides well with the lament width dened by the above mentioned charge ring. This is a valuable contribution to the understanding of the filament interaction.
Projektbezogene Publikationen (Auswahl)
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Interaction of current laments in dielectric barrier discharges with relation to surface charge distributions, New Journal of Physics, 11, 103034 (2009)
L. Stollenwerk
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Interaction of current laments in a DBD system, Plasma Phys. Control. Fusion, 52, 124017 (2010)
L. Stollenwerk
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Electric Charging in Dielectric Barrier Discharges with Asymmetric Gamma-Coecients, Contrib. Plasma Phys., 51, 61-67 (2011)
L. Stollenwerk and U. Stroth
