Radiation of plasma diffuse jets in the wavelength range of 120–1000 nm at air pressures of 0.2–1.5 Torr

At present, studies of various atmospheric discharges in the stratosphere and mesosphere are ongoing. Considerable attention is paid to the study of the spectral characteristics of the radiation of red sprite plasma, including columnar ones. However, field studies require large material costs. Therefore, in parallel, work is being carried out on experimental modeling of the properties of high-altitude discharges in laboratory conditions at low atmospheric air pressures. The article presents the results of studies of the spectral properties of plasma diffuse jets (PDJs), which are analogs of columnar sprites. PJs were formed using a pulse-periodic barrier discharge in quartz tubes at pressures of 0.2–2 Torr in air and nitrogen. In the spectral range from 120 to 1000 nm, data were obtained on the relative spectral density of radiation energy on three bands of the nitrogen molecule and one band of the molecular nitrogen ion both from the end of the quartz tube and from its side surface. It was found that in the emission spectra of the PDS from the end of the tube and its side surface near the electrodes, the intensity ratio of the bands of the second positive (2+) and first negative (1-) nitrogen systems changes in favor of the 1- system. Radiation was recorded in the vacuum-ultraviolet region of the spectrum on the $a^1\Pi_g-X^1\Sigma_g^+$ band of nitrogen molecules and on the lines of atomic nitrogen, the intensity of which increased with decreasing air pressure. It was confirmed that in the PDS, the spectral density of the radiation energy $W$ of the 2+ nitrogen system bands exceeds the $W$ of the 1+ nitrogen system bands.