Spectroscopic measurements on discharges along a dielectric surface

Abstract

Spectroscopic measurements have been made on quasilinear surface discharges over dielectric slabs. The first time-resolved spectra in the range 200-800 nm have been obtained; we define the light emitting centers (N2 molecular bands in a first period and atomic lines in a second one) and the dielectric substrate effect. We give the form of the rotational temperature variations and the upper value of the electron temperature (5 eV) in the first period. The spatial dimension of this phase seems to be constant at about 23 mm. In the second period the electron densities calculated from the Stark broadening width of the Hα and Hβ lines vary in 8×10-7 s from 7×1017 to 2×1016 cm-3. In the same period, the temperature which is obtained by Saha's law using the intensity ratios of ionized atomic and neutral lines (oxygen O+,O) and nitrogen (N+,N) decreases from 24 000 to 15 000 K. Using these results we estimate the cross-sectional area of the discharge to be ≅65 000 μm 2.