Investigations on the afterglow of a thin cathode discharge in argon at atmospheric pressure

Sebastian Mohr (1) , Beilei Du (1) , Dirk Luggenhölscher (1) , Uwe Czarnetzki (1)

1 Institute for Plasma and Atomic Physics

A thin cathode discharge consists of two electrodes separated by a dielectric layer with a thickness of ca. 100 µm. The shape of the anode can be chosen arbitrarily, while the thickness of the cathode is also about 100 µm. Through this " sandwich ", a hole with a diameter of 200 µm is drilled. When such a device is operated at pressures of several 100 hPa, it shows a self-pulsing behaviour in which high electron densities of several 3 16 10 − cm are reached. Electrical measurements showed, that this can be explained by the repeated ignition of a shortliving spark discharge. Due to the high pressure and the related high collision frequencies, the afterglow of this discharge was expected to last several 10 ns. Instead, lifetimes of several 100 ns were observed. In order to identify the mechanisms responsible for this long living afterglow, a kinetic model of the afterglow was developed. As a result, Penning-ionization, superelastic collisions with both atoms in excited states and excimers were found to play a crucial role in the production and heating of electrons.

Mots clés: 52.25.Dg; 52.70.Ds; 52.70.Kz; 52.75.Xx; 52.80.Mg; Submitted to:

Sebastian Mohr, Beilei Du, Dirk Luggenhölscher, Uwe Czarnetzki. Investigations on the afterglow of a thin cathode discharge in argon at atmospheric pressure. Journal of Physics D: Applied Physics, 2010, 43 (29), pp.295201. ⟨10.1088/0022-3727/43/29/295201⟩. ⟨hal-00569656⟩