Generation and diagnostics of atmospheric pressure dielectric barrier discharge in argon/air

Abstract

In this paper, a technique for the determination of electron temperatures and electron densities in atmospheric pressure argon/air discharge by the analysis of optical emission spectra (OES) is reported. The discharge is produced using a high voltage (0-20 kV) power supply operating at a frequency of 27 kHz in parallel electrode system, with glass as dielectric. The dielectric layers covering the electrodes act as current limiters and prevent the transition to an arc discharge. Optical emission spectra in the range of 300 nm to 850 nm have been recorded for the discharge with different inter electrode gap keeping electric field constant. Electron temperature T_e and electron density n_e have been estimated from electrical and optical methods. Electron density has been calculated using power balance method. The optical methods are related with line intensity ratio from the relative intensities of Ar-I and Ar-II lines in Argon plasma. The electron density calculated by using line intensity ratio method has been compared with the electron density calculated by stark broadening method. The effect of dielectric thickness on plasma parameters has also been studied and it has been found that T_e and n_e increase as thickness of dielectric decrease for same inter electrode distance and applied voltage.