Research on Ion Enhancement Effect in Micro-gap Gas Discharge

• Published in: Journal of the Physical Society of Japan 2020-09, Vol.89 (9), p.94501
• Main Authors: Sun, Yanzhou, Wang, Linhua, Dong, Keliang, Liu, Xuguang
• Format: Article
• Language: English
• Subjects: Breakdown; Cathodes; Density; Electric field strength; Electric fields; Electric potential; Electrodes; Field emission; Gas discharges; Voltage
• ISSN: 0031-9015; 1347-4073
• DOI: 10.7566/JPSJ.89.094501

To study the deviation from the Paschen curve under the micro-gap, the DC breakdown experiment with the electrode distance of 1–100 µm was carried out under atmospheric pressure in air. By deriving the approximate analytical formula of the ion number density near cathode, it is found that the higher ion number density near cathode will produce an additional electric field with the increase of applied voltage in the gap range of 1 to 10 µm. The additional electric field strength decreases with the increase of the gap, so there is a strong ion enhancement effect at the micro-gap. Combined with the ratio of the effective secondary coefficient γ′ of the ion enhancement effect and the secondary coefficient γ of Townsend, the curve of the change of γ′/γ with the electrode distance shows that the discharge process is dominated by the field emission of the ion enhancement effect at several microns, and the effect gradually weakens with the increase of the distance. In the range of 10 and 100 µm, with the increase of electrode distance, the breakdown voltage basically conforms to the classic Paschen curve, and the discharge process can be explained by Townsend theory.