Electromagnetic Signal Processing to Diagnose the Electron Density in Gas Discharge

The electromagnetic radiation signal from dielectric barrier discharge in air at atmospheric pressure has been processed to investigate the electron density during the afterglow period. Experimental results show that many short-lived discharge filaments appear on the electrode of the surface discharge generator in air at atmospheric pressure. The number of the discharge filaments increases with increasing the applied voltage. The discharge current waveforms consists of many short-lived pulses with duration of about several nanoseconds, which oscillates with impedence resulting from the ion oscillation from the plasma. Through analyzing the oscillation frequency, the electron density can be calculated and the electron density in the order of 8 × 10¹⁹ m^-3 can be reached during the afterglow discharge period in our experiment.