Measurement of ion density in an atmospheric pressure argon with pin-to-plate dielectric barrier discharge by resonance of plasma radiation

The measurements of the ion densities in the atmospheric AC barrier corona argon discharge are carried out by receiving and analyzing the frequencies of the electromagnetic radiation emitted from the plasma. An auxiliary excitation source composed of a pin-to-pin discharge system is introduced to excite the oscillations of the main discharge. To analyze the resonance mechanism, a complemented model based on a one-dimensional description of forced vibrations is given. Calculations indicate that Ar₂⁺ is the dominant ion (∼89% in number density). By analyzing resonance frequencies, the ion densities of Ar₂⁺ are in the order of 10¹⁹∼10²⁰m⁻³ and increase slowly as the applied voltage increases