Ignition and Propagation of an Atmospheric-Pressure Helium Plasma Jet

The ignition and propagation of an atmospheric-pressure plasma jet is examined using fast imaging techniques. The plasma jet consists of a single electrode, fabricated using a transparent and conductive polymer film, wrapped around a quartz dielectric tube; this allows the entire ignition and propagation process to be observed without the usual obstruction of a nontransparent electrode. It is shown that the discharge is always triggered at the electrode edges and that the plasma propagation mechanism differs significantly depending on the polarity of the applied voltage.