Characteristics of Coaxial Grid Discharge Plasma and Its Effect on Microwave Transmission

This study designed and constructed a setup for generating direct current glow discharge plasma using a coaxial grid configuration. The volt-ampere characteristics and Paschen curves of the plasma generated by this setup under different conditions are investigated. The electron excitation temperature of the plasma is calculated using the Boltzmann slope method. By comparing the volt-ampere characteristics and Paschen curves under different conditions, it is observed that the voltage across the electrodes and the current passing through them are positively correlated. Additionally, compared to a non-perforated anode electrode, the voltage, and current variations are more pronounced in the case of a perforated anode electrode. Furthermore, the breakdown voltage of the electrodes follows the variation trend of the Paschen curve with respect to electrode spacing and gas pressure. The electron excitation temperature of the plasma generated by electrode discharge, calculated using the Boltzmann slope method, increases with an increase in gas pressure. The distribution of the electron excitation temperature of the plasma is around 5000 K. Moreover, at the same gas pressure, an increase in the electrode perforation rate leads to a higher electron excitation temperature of the plasma. By measuring the effects of plasma generated by coaxial grid electrode discharge on microwave transmission, experimental results indicate the existence of an optimal pressure value that maximizes microwave attenuation. Meanwhile, the influence of the perforation rate on microwave transmission requires further investigation.