Accurate spectroscopic studies of streamer discharges. 1. Experimental results

Accurate spectroscopic studies of the positive point-to-plane DC repetitive streamer corona in short air gaps have been presented. Measurements of local luminosity waveforms with high resolution in time (0.3÷0.7 ns), in space (0.01÷0.1 mm) and in wavelengths (0.05÷0.5 nm) have been conducted. The luminosity waveforms of the second positive and first negative systems of molecular nitrogen have been recorded at different point of observation across whole the discharge gap with successive step shift in space along the gap axis. Local electric field and electron number density in primary filamentary streamer wave have been determined by the relative and absolute luminosity intensity method to be in mid-gap, consequently: 300÷315 Td, i.e. 80÷86 kV/cm and (0.8÷1.2)×10¹³cm^-3.