Role of the atomic argon on the plasma characteristics of O2/N2 gas mixture

The current work conducts a detailed investigation on adding atomic argon to the O2/N2 plasma in direct current (DC) and radiofrequency (RF) atmospheric plasma jets (APJs) using Optical Emission Spectroscopy (OES). The plasma density, rotational, vibrational, and excitation temperatures are determined by studying emission spectra obtained near the DC and RF APJs plume. The NO and OH bands are seen in the emission spectrum. The three N2 vibrational bands and the Ar I spectral emission line intensities are used to calculate the vibrational and excitation temperatures. The emission intensity from argon ions increases with larger argon contributions in the Ar/O2/N2 gaseous mixture in both APJs. Furthermore, when the argon contribution to the mixture is high and nitrogen is greater than oxygen, the plasma electron density decreases as the rotational, vibrational, and excitation temperatures rise. However, for both the generated APJs, when oxygen contributes more than nitrogen and increases plasma electron density, the vibrational and rotational temperatures fall. However, larger input DC and RF powers result in higher plasma density and rotational, vibrational, and excitation temperatures for both DC and RF APJs. Furthermore, the molecular oxygen and nitrogen dissociation rate increases as the amount of argon in the mixture increases.