A Simple Model for the Calculation of Plasma Impedance in Atmospheric Radio Frequency Discharges

In atmospheric radio-frequency (rf) discharges, the plasma parameters, such as elec- tron density, sheath thickness and sheath voltage, are not easy to be probed experimentally, while the electrical characteristics, such as impedance, resistance and reactance, are relatively conve- nient to be measured. In this paper we presented a simple theoretical model derived from the fluid description of generated plasmas without considering the circuit model, to investigate the relationship between the plasma impedance and plasma parameters. By introducing a relaxation frequency, the plasma impedance could be predicted by formulas presented in this study, and the mean electron density and sheath thickness can also be calculated from the measured or simulated impedance and reactance, respectively.