Time-resolved Optical Imaging of a Cylindrical Dielectric Barrier Micro- Discharge with TCO Electrode

Diagnostics of micro-discharges operated at around atmospheric pressure present a significant challenge due to their small size (typically < 1 mm). In particular, the main discharge region is inaccessible for diagnostic methods, including optical emission spectroscopy, due to the presence of the electrode. Here, a transparent conductive oxide (TCO) electrode is used to allow direct optical access to the discharge region inside the electrode. It is shown that, for the simpler case of a single driving electrode, the discharge forms just outside of both electrode edges on the axis of the cylindrical tube. The time evolution of the discharge reveals complex time dependant behaviour including plasma bullet (both into the electrode and away from the electrode) and streamer formation. 1