Spectroscopic, electrical diagnostics of dual-power electrodes atmospheric pressure argon plasma plume discharge characteristics

摘要

In this paper, an atmospheric pressure argon plasma plume generated by sinusoidal power input of moderate frequency (kHz range) and designed with dual-power electrodes is characterized and studied. Particularly, the effect of driving frequency in the 60-130 kHz range on the argon plasma discharge characteristics is investigated based on a detailed electrical and spectroscopic diagnostics. And, temporal and spatial optical emission spectroscopy is used to measure the plasma parameters, of which the excitation electron temperature is determined by the Boltzmann's plot method whereas the electron density is estimated using the stark broadening of the hydrogen Balmer H_β line. It is shown that at constant applied voltage and gas flow rate, the increase of driving frequency in the range of 60-100 kHz exerts no significant influences on discharge parameters. While once the driving frequency exceeds a certain value of about 100 kHz, the discharge becomes intense abruptly and the corresponding discharge parameters increase drastically with the driving frequency. Detailed analysis about the effect of driving frequency on discharge characteristics is presented and two different dominant electron loss mechanisms, namely transport-dominated loss and diffusion-dominated loss, are proposed to account for the distinct effects of the driving frequency on argon discharge characteristics.