Plasma emission spectroscopy diagnosis of a direct current reverse-brush electrode discharge

In this work, emission spectra measurements from direct current (DC) reverse-brush discharge plasmas were used to elucidate the energy level transition processes corresponding to each spectral line based on the mechanism of emission spectrum generation. The axial distribution patterns of the spectral line intensity and the electron excitation temperature in the electrode gap and post-cathode space were systematically investigated. By comparing the acquired experimental results, it was observed that both the relative intensity of the plasma emission spectra and the electron excitation temperature in the electrode gap were higher than in the post-cathode space, while their axial distribution trends exhibited an initial increase followed by a decrease. Additionally, the impact of the discharge gas pressure, reverse-brush electrode thickness, and the number of electrode openings on the emission spectral line intensity and electron excitation temperature in the electrode gap were explored. Explanations for the underlying physical mechanisms were also provided.