AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS-TuM

Paper PS-TuM1
Instabilities in a Dielectric Barrier Discharge at Atmospheric Pressure

Tuesday, November 5, 2002, 8:20 am, Room C-103

Session: Atmospheric Pressure and Other Emerging Plasma Applications
Presenter: E. Aldea, Eindhoven University of Technology, The Netherlands
Authors: M.C.M. Van de Sanden, Eindhoven University of Technology, The Netherlands
E. Aldea, Eindhoven University of Technology, The Netherlands
C.P.G. Schrauwen, TNO TPD, The Netherlands
Correspondent: Click to Email
Due to their enormous potential for cost-efficient industrial applications, atmospheric low temperature (300-500 K) plasmas at atmospheric pressure received large attention in recent years. From the points of view of power density and plasma stability the most efficient solution was proved to be the dielectric barrier configuration in which the electrodes are covered with a insulator. The procedure used to generate plasma is simple but the physical mechanism underlying the plasma generation is still unclear. The generation of homogeneous plasma at atmospheric pressure is assumed to be related to the gas pre-breakdown pre-ionisation by metastable-metastable collisions,@footnote 1@ but there are not yet unambiguous experimental evidences of a significant pre-ionization due to this mechanism. In this paper the work was focussed on the investigation of the role of metastables in the excitation or ionisation processes in a plasma generated in Ar , nitrogen and air between two electrodes (electrode gap 0.3-5 mm) covered by a dielectric mounted in a gas tight cabinet. A study of dependence of plasma stability and filamentation on the electrode gap, surface temperature, voltage pulse frequency or shape was also performed and the optimum conditions range was defined. The importance of metastables is evaluated on basis of the plasma rovibrational and excitation temperatures derived from the optical emission spectroscopic data, and on the study of the correlation between temporal dependence of the plasma emission and of the current pulse. It is demonstrated that metastable-metastable collisions cannot be responsible for a significant pre-ionization. Therefore other factors must play a role in plasma stability. @FootnoteText@ @footnote 1@N. Gherardi, G. Gouda, E. Gat, A. Ricard, F. Massines , Plasma Sources Sci. Technol. 9 (2000), 340.