Spatially and temporally resolved optical spectroscopic investigations inside a self-pulsing micro thin-cathode discharge

Beilei Du (1) , Mitsutoshi Aramaki (2) , Sebastian Mohr (1) , Yusuf Celik (1) , Dirk Luggenhölscher (1) , Uwe Czarnetzki (1)

1 Institute for Plasma and Atomic Physics
2 Department of Electrical Engineering and Computer Science

A fiber probe is developed to investigate the temporal development and the spatial distribution of the population density of argon 1s 5 state and the emission in the afterglow in a self-pulsing micro thin-cathode discharge (µTCD) at atmospheric pressure. The fiber probe with a diameter (125 µm) of about half the discharge diameter (200 µm) is moved along the discharge axis. A tunable diode laser beam at 696.73 nm at resonance with the argon 1s 5 → 2p 2 transition is coupled into the far end of the fiber probe. The spatially differentiated absorbance yields the axial distribution of the 1s 5 state. In addition, the fiber is used to determine similarly the spatially resolved optical emission of various argon lines. Both the emission and the absorption profiles confirm that, in the afterglow, the plasma is strongly localized inside the hole of the discharge. Qualitatively, the measurements agree very well with the results of a zero-dimensional simulation. The long living afterglow is related to the high population density of the metastable atoms.

Mots clés: Physical Sciences

Beilei Du, Mitsutoshi Aramaki, Sebastian Mohr, Yusuf Celik, Dirk Luggenhölscher, et al.. Spatially and temporally resolved optical spectroscopic investigations inside a self-pulsing micro thin-cathode discharge. Journal of Physics D: Applied Physics, 2011, 11 (25), pp.252001. ⟨10.1088/0022-3727/44/25/252001⟩. ⟨hal-00627536⟩