The influence of grounded electrode positions on the evolution and characteristics of an atmospheric pressure argon plasma jet

An atmospheric pressure plasma jet (APPJ) in Ar with various grounded electrode arrangements is employed to investigate the effects of electrode arrangement on the characteristics of the APPJ. Electrical and optical methods are used to characterize the plasma properties. The discharge modes of the APPJ with respect to applied voltage are studied for grounded electrode positions of 10 mm, 40 mm and 80 mm, respectively, and the main discharge and plasma parameters are investigated. It is shown that an increase in the distance between the grounded electrode and high-voltage electrode results in a change in the discharge modes and discharge parameters. The discharges transit from having two discharge modes, dielectric barrier discharge (DBD) and jet, to having three, corona, DBD and jet, with increase in the distance from the grounded to the high-voltage electrodes. The maximum length of the APPJ reaches 3.8 cm at an applied voltage of 8 kV. The discharge power and transferred charges and spectral line intensities for species in the APPJ are influenced by the positions of the grounded electrode, while there is no obvious difference in the values of the electron excited temperature (EET) for the three grounded electrode positions.