A coplanar-volume coupled discharge based on pre-ionization: Physical and chemical properties

A coplanar-volume coupled discharge utilizing a capillary coplanar dielectric barrier discharge (CDBD) as a pre-ionization source and employing a negative direct current (DC) voltage to prompt plasma propagation from the dielectric surface to the air gap is proposed and experimentally investigated. Optical-electrical properties, spatial-temporal evolution of plasma, and active species generation are systematically studied to provide in-depth insights into the plasma characteristics of coplanar-volume coupled discharge based on pre-ionization. Compared to traditional dielectric barrier discharge, this approach reduces the inception voltage and significantly enhances the discharge intensity. Spatial-temporal evolution of plasma morphology demonstrates two distinct discharge processes occurring in coplanar-volume coupled discharge: coupled primary discharge and coupled secondary discharge. These processes are developed from the coplanar primary discharge and coplanar secondary discharge in capillary CDBD, respectively. Through analyzing the effects of pulse voltage and negative DC voltage on the physical and chemical properties of plasma, coplanar-volume coupled discharge based on high pre-ionization exhibits strong plasma luminous intensity, elevated discharge energy, and heightened chemical activity.