Düsseldorf 2007 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 10: Niedertemperaturplasmen

P 10.2: Vortrag

Dienstag, 20. März 2007, 11:45–12:00, 6F

Turing scenario of the transition from Townsend to glow discharge mode — •Shalva Amiranashvili, Svetlana Gurevich, and Hans-Georg Purwins — Institut für Angewandte Physik, Münster, Germany

We theoretically consider destabilization of the low-current Townsend discharge mode due to volume charge effect. Usual destabilization scenario is due to excitation of subnormal current oscillations that in turn transfers the discharge in the glow mode. In the latter the electric current is constricted and flows through a single cathode spot. We demonstrate that in the plane-parallel discharge cell with the high-ohmic (semiconductor) cathode another scenario is also possible. Here, the most unstable current harmonic is spatially nonuniform and the instability develops "in space". Therefore, several current spots appear between the electrodes. The instability is shown to be similar to Turing's instability that is common for many chemical and biological systems. Our results provide theoretical basis for qualitative understanding of numerous forms of constricted discharge that can be observed in a system with the high-ohmic cathode.