Eur. Phys. J. D (2014) 68: 319
https://doi.org/10.1140/epjd/e2014-50343-8

Regular Article

Stability of alternating current gliding arcs

¹ Department of Wind Energy, Section of Composites and Materials Mechanics, Technical University of Denmark, DTU Risø Campus, Frederiksborgvej 399, 4000 Roskilde, Denmark
² Department of Physics, Technical University of Denmark, Fysikvej, 2800 Kgs. Lyngby, Denmark
³ Division of Combustion Physics, Lund University, P.O. Box 118, 22100 Lund, Sweden

^a e-mail: yuki@dtu.dk

Received: 30 April 2014
Received in final form: 4 August 2014
Published online: 28 October 2014

Abstract

A gliding arc is a quenched plasma that can be operated as a non-thermal plasma at atmospheric pressure and that is thus suitable for large-scale plasma surface treatment. For its practical industrial use the discharge should be extended stably in ambient air. A simple analytical calculation based on Ohm’s law indicates that the critical length of alternating current (AC) gliding arc discharge columns can be larger than that of a corresponding direct current (DC) gliding arc. This finding is supported by previously published images of AC and DC gliding arcs. Furthermore, the analysis shows that the critical length can be increased by increasing the AC frequency, decreasing the serial resistance and lowering the gas flow rate. The predicted dependence of gas flow rate on the arc length is experimentally demonstrated. The gap width is varied to study an optimal electrode design, since the extended non-equilibrium discharge can be extinguished due to the ignition of an arc discharge at the closest electrode gap. It is experimentally found that as the gap is wider, the discharge column tends to be longer.