Investigation the effect of planar anode area on Characterization of low-pressure argon plasma

Abstract

This research investigated the effect of both the applied voltage and the anode area on the electrical and plasma properties of a DC glow discharge in low-pressure argon gas. The electrical properties included current-voltage (I-V) curves and Paschen's curves, while the plasma parameters included electron temperature and number density. The plasma was generated between two copper electrodes separated by a constant distance of (4 cm), using anodes of different diameters of (2, 4, 5, and 6 cm). The plasma was characterized by optical emission spectroscopy (OES), which was used to estimate the electron temperature (Te) and number density (ne). The experimental results showed that the discharge operates within an anomalous glow regime. Furthermore, decreasing the anode area led to a higher breakdown voltage required to initiate the discharge, while increasing the anode area resulted in higher spectral emission line intensity, electron temperature, and number density. When the anode diameter changed from (2-6) cm, the electron temperature ranged from (0.389-0.393) eV, while the electron density ranged from (3.26×10¹⁵ - 9.23×10¹⁵) cm⁻³. These results confirm the influential role of anode geometry in the distribution of the electric field and the processes of ionization and excitation, and thus in determining the electrical and plasma characteristics of the discharge.