An atmospheric pressure self-pulsing micro thin-cathode discharge

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

1 Institute for Plasma and Atomic Physics

A micro thin cathode discharge (µTCD) is a modified micro hollow cathode discharge (MHCD) where the anode is much thicker than the one in a MHCD, which allows a stable operation at atmospheric pressure. The µTCD was operated at different pressures in argon by a DC voltage. At atmospheric pressure, the µTCD operates in a self-pulsing mode with current peaks with a duration of a few nanoseconds and a current density up to 10 5 A/cm 2, supplied by the charge stored in the capacitance of the discharge device. The plasma emission was observed by an ICCD camera. Both, the voltage- current characteristic and the ICCD image indicate that this self-pulsing is due to a periodic ignition of a spark discharge. The electron density was measured by the Stark broadening of the H β -line with an admixture of 1% hydrogen. In the periodic spark mode the electron density is of the order of 10 16 cm -3. The direct measurement of the discharge current in these kind of discharges is not possible, since it is driven by the inherent capacitance of the discharge device. Therefore, an electrical model including stray capacitances is set up. The modelled results agree very well with the measured currents and voltages.

Mots clés: 52.25.Os; 52.50.Dg; 52.50.Nr; 52.70.Ds; 52.70.Kz; 52.80.Mg

Beilei Du, Sebastian Mohr, Dirk Luggenhölscher, Uwe Czarnetzki. An atmospheric pressure self-pulsing micro thin-cathode discharge. Journal of Physics D: Applied Physics, 2011, 44 (12), pp.125204. ⟨10.1088/0022-3727/44/12/125204⟩. ⟨hal-00604888⟩