SOME SPECIAL FEATURES OF MOLECULAR SPECTRA EMITTED BY HIGH ENTHALPY ATMOSPHERIC PRESSURE NITROGEN PLASMA JETS

In the 220−470nm range are obtained and investigated the emission molecular spectra of atmospheric pressure nitrogen plasma jets produced by a high current plasmatron with a divergent vortex stabilized by the working gas channel. The spectra have been taken at different distances downstream from the cathode, both the region nearest to the cathode and the far relaxation zone included, and at different radial distances from the jet axis. High spectral resolution attained (~ O.Olnm) has allowed vibrational and rotational structures of the N₂⁺ First Negative ( Β²Σ_u⁺ − Χ²Σ_g⁺ ) and of the N₂ Second Positive ( C³Π_u − Β³Π_g )Systems to be essentially resolved; in so doing radical changes in the spectra when moving along the jet are found. Why this is the case is qualitatively discussed. Some plasma parameters are further assessed and the question of whether there are the jet sections with a locally equilibrium plasma is touched on.