An optical emission of plasma jet excited by barrier discharge in argon-air and he-air mixtures


Background. Atmospheric pressure plasma jets are intensively studying during last years due to its unique parameters and applications. The best carrier of such type of plasma is the capillary barrier discharge. The purpose of this work is to study the emission spectra of this plasma jets generated in helium and argon inert gases also as in helium-air and argon-air mixtures.
Materials and methods. We explored the optical method to study the molecular emission spectra of all studied plasma jets. Emitted spectra were registered using grating grid monochromator and HS 101H CCD-camera.
Results. In spectral range 300-900 nm it was experimentally investigated the luminescence of atmospheric pressure plasma jets excited by barrier discharge in Argon-air and Helium-air mixtures. It was shown that emitted spectra are represented mainly by electron-vibrational transitions of the second positive system of neutral nitrogen molecules N2 (C 3Пu →B 3Пg).
Conclusion. Experimentally were investigated and analyzed luminescence spectra of plasma jets formed by barrier discharge in helium, argon and their mixtures with air. It was established that the emission intensity of helium-air jet is thirdly much more than argon-air jet, predominantly due to Penning ionization

Keywords: plasma jet, barrier discharge, nitrogen molecule