Spatially and temporally resolved measurements of argon metastable atoms in the effluent of a cold atmospheric pressure plasma jet

R Bussiahn (1) , E Kindel (1) , H Lange (1) , K.-D Weltmann (1)

1 INP - Leibniz Institute for Plasma Science and Technology

Although atmospheric pressure plasma jets (APPJ) have been used for several years in wide fields of application, there is still lack of knowledge about physical aspects, namely the phenomenon of spatiotemporally localized luminous effects in the effluent of APPJ, so called " plasma bullets ". The present paper reports on investigations on the effluent of a low frequency (kHzrange) driven APPJ in argon atmosphere. To gain insight into the spatiotemporal structure of the effluent, laser absorption measurements, probing the optical depth of the 4s 3 P 2 − 4p 3 D 3 transition of argon (811.531 nm), which is proportional to the column density of the metastable 4s 3 P 2 argon atoms and investigations with an intensified video camera were performed. Simultaneous recordings of the discharge current show that plasma bullets are connected only to a certain current pulse in a series of four pulses of the discharge cycle. A good correlation between the propagation speeds of the plasma bullets (5-20 km/s) and of the generation zone of metastable argon atoms in the effluent of the APPJ (8-25 km/s) was found. Both, the appearance of plasma bullets and spatiotemporal evolution of the generation zone of metastable atoms can be explained by the effect of a self-propagating ionization front.

Mots clés: Physical Sciences

R Bussiahn, E Kindel, H Lange, K.-D Weltmann. Spatially and temporally resolved measurements of argon metastable atoms in the effluent of a cold atmospheric pressure plasma jet. Journal of Physics D: Applied Physics, 2010, 43 (16), pp.165201. ⟨10.1088/0022-3727/43/16/165201⟩. ⟨hal-00569580⟩