Characteristics of argon discharge plasma jet: comprehensive effects of discharge voltage, gas flow rate, and external magnetic field

Abstract

Atmospheric pressure plasma jet has garnered significant attention for their vast potential across diverse fields, with the discharge conditions playing a pivotal role in shaping their physicochemical properties and ultimately determining their application efficacy. Factors such as discharge voltage, gas flow rate, and the introduction of an external magnetic field intricately influence the performance of plasma jet. The combined effects of any two of these factors can yield enhanced outcomes, while they also introduce complexity to the discharge phenomena. However, there is currently a lack of research on the combined effects of external magnetic field, discharge voltage, and gas flow rate on the characteristics of plasma jets, making it difficult to comprehensively evaluate the discharge characteristics of plasma jet under multiple discharge conditions. Therefore, this paper focuses on an AC excited atmospheric pressure argon plasma jet and investigates the combined effects of external magnetic field, discharge voltage, and gas flow rate on various characteristic parameters of the plasma jet, encompassing macroscopic morphology, discharge power, gas temperature <i>T</i><sub>g</sub>, electron excitation temperature <i>T</i><sub>exc</sub>, electron density <i>n</i><sub>e</sub>, emission intensity of excited state Ar* particles, and number density of ground state ŸOH particles by using methods of camera shooting, and electrical parameter measurement, spectroscopic analysis of emission and absorption spectra. The results show that the effect of discharge voltage on the characteristic parameters of the plasma jet remains consistent, unaffected by variations in gas flow rate or the presence of an external magnetic field; an increase in discharge voltage consistently improve jet performance by enhancing the discharge power, extending the plasma plume length, elevating the gas temperature <i>T</i><sub>g</sub> and electron excitation temperature<i> T</i><sub>exc</sub>, increasing the electron density <i>n</i><sub>e</sub> and emission intensity of excited state Ar* particles, as well as the number density of ground state ŸOH particles. The addition of an external magnetic field can improve the jet performance without significantly changing the discharge power, and the extent of this improvement is influenced by the mode of magnetic field action. Notably, when the magnetic field selectively targets the plasma plume, excluding direct interaction with electrodes discharge area, the enhancement in jet performance is most pronounced. The effect of gas flow rate on jet performance becomes intricate, intertwined with the effects of voltage and the external magnetic field. When an external magnetic field is present, excessive voltage and gas flow rate may reduce the number density of ground state ŸOH particles generated by plasma jet. This underscores the need for a nuanced understanding when optimizing jet performance under multiple discharge conditions. Simply combining the optimal conditions for each individual factor does not guarantee the achievement of peak jet performance when all three discharge conditions act in concert. This study offers valuable insights into the discharge characteristics of plasma jet under varying discharge conditions, providing a guidance for optimizing performance of plasm jet and fostering the advancement of atmospheric pressure plasma jet technology across diverse application domains.