Pulsed discharge plasma and its application is one of the promising directions in civilian areasof pulsed power technology. In order to promote the research and development ofthe theory and application technology for pulsed discharge plasma, in thispaper, recent progress on the mechanism of nanosecond‐pulse gas discharge andthe characteristics and applications of typical pulsed plasma at the Instituteof Electrical Engineering, Chinese Academy of Sciences is reviewed. Firstly,progress on mechanism of nanosecond‐pulse discharge based on runaway electronsand measurement technology of runaway electrons is introduced. Then, thecharacteristics of three typical discharges, including direct‐driven pulseddischarge, pulsed dielectric barrier discharge and pulsed plasma jet, arereviewed. Furthermore, typical plasma applications of pulsed plasma on surfacemodification and methane conversion are presented.

Polymer materials, such as polymethylmethacrylate (PMMA), are widely used as insulators in vacuum. The insulating performance of a high-voltage vacuum system is mainly limited by surface flashover of the insulators rather than bulk breakdown. Non-thermal plasmas are an efficient method to modify the chemical and physical properties of polymer material surfaces, and enhance the surface insulating performance. In this letter, an atmospheric-pressure dielectric barrier discharge is used to treat the PMMA surface to improve the surface flashover strength in vacuum. Experimental results indicate that the plasma treatment method using Ar and CF₄ (10:1) as the working gas can etch the PMMA surface, introduce fluoride groups to the surface, and then alter the surface characteristics of the PMMA. The increase in the surface roughness can introduce physical traps that can capture free electrons, and the fluorination can enhance the charge capturing ability. The increase in the surface roughness and the introduction of the fluoride groups can enhance the PMMA hydrophobic ability, improve the charge capturing ability, decrease the secondary electron emission yield, increase the surface resistance, and improve the surface flashover voltage in vacuum.