This paper is mainly devoted to the comparison between the calculation and experimental results of primary and secondary streamer development in a point-to-plane positive corona discharge in dry air at atmospheric pressure. The qualitative agreement between experimental and calculation results based on the hydrodynamics approximation shows that the O radical is mainly produced in the secondary streamer which is in good agreement with the recent literature measurements using TALIF diagnostics. However, the O radical production yield (in terms of radicals produced per energy injected) is more efficient in the primary streamer than in the secondary one. The main positive corona discharge characteristics are revisited using fast electrical and optical ICCD and streak camera measurements. The calculation shows two streamer radii of, respectively, 10 µm (associated with the radial extension of a high electron density region) and 200 µm (corresponding to the extension of the radial space charge electric field).

This work is devoted to the analysis of experimental results obtained in dry air at atmospheric pressure in a positive point-to-plane corona discharge under a pulsed applied voltage in the cases of anodic mono-and multi-tips. In the mono-tip case, the peak corona current is analysed as a function of several experimental parameters such as magnitude, frequency and duration of pulsed voltage and gap distance. The variation of the corona discharge current is correlated with the ozone production. Then in the multi-tip case, the electrical behaviour is analysed as a function of the distance between two contiguous tips and the tip number in order to highlight the region of creation active species for the lowest dissipated power. Intensified charge-coupled device pictures and electric field calculations as a function of inter-tip distance are performed to analyse the mutual effect between two contiguous tips. The optical emission spectra are measured in the UV-visible-NIR wavelength range between 200 nm and 800 nm, in order to identify the main excited species formed in an air corona discharge such as the usual first and second positive systems with first negative systems of molecular nitrogen. The identification of atomic species (O triplet and N) and the quenching of NOγ emission bands are also emphasized.

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This paper is mainly dedicated to the experimental electric and spectroscopic analysis of positive corona discharges in the case of point to plane configuration, generated in nitrogen at atmospheric pressure. The maximum corona current (a few hundreds of mA), the average current (a few μA) and the average propagation velocity (a few 10 7 cm/s) are analyzed with the variation of the applied voltage (a few kV) and the gap distance (not exceeding 16 mm). By using an ICCD camera, the dynamics of the discharge during the propagation of primary and secondary streamers across the gap distance was analyzed. Spectroscopic study is emphasized in a spectral range from 200 nm up to 500 nm, to determine the important excited species present in the gaseous environment such as the second positive and the first negative systems (SPS and FNS respectively). The identification of the quenching NO γ emission bands is also emphasized.

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