Study of an atmospheric-pressure discharge in air

The characterization of has been active region of the corona discharge, it is critical and important for several applications. In this work, it investigated an air discharge at atmospheric pressure between a needle electrode and a flat metal cathode, as well as between a needle electrode and a cathode immersed in water. The voltage and current of the plasma discharge were analyzed; the power used was of 14 kW. The air discharge was analyzed by optical emission spectroscopy (OES), using a spectrometer (Model HR2000CG-UV-NIR). The optical emission spectroscopy were measured in the UV-visible-NIR wavelength range between 200 nm and 1100 nm, in order to identify the excited species formed in a corona air discharge. The species observed were: NO transitions A²Π → X²Π at 222.2, 272.2 nm; NH transition, A³Π→X³Σ at 336.1 nm; N₂⁺ transitions B²Σ_u→X²Σ_g at 391.4, 423.7, 427.8 and 495.73 nm; N₂⁺ at 567.95 and 593.17 nm; O at 777.1, 844.6 and 869.56 nm; H₂O at 618.8 and 657.8 nm The electron temperature (Te) and electron density (ne) were evaluated using the Boltzmann and Saha equations, they were found to be 7.07 eV and 2.43 × 10¹⁵ cm^-3 respectively.