Transient Evolution of Argon Radio Frequency Atmospheric Pressure Discharge After the Very First Breakdown

The very first breakdown in argon radio frequency (RF) atmospheric pressure discharge was realized by pulse modulation with a sufficiently long off-time. The afterward nonsteady temporal stage was monitored with voltage/current probes and a fast camera. Experimental results show that conventionally observed uniform RF atmospheric pressure discharge glows at steady phrase stem from the initial local weak glow through the intermediate stages of filamentation, splitting, branching, expansion, decay, and homogenization. Such a process should also possibly occur after the breakdown of a continuous wave RF atmospheric pressure discharge. During the filamentary stage of the discharge, unusual parallel branching is originated from centers of axial main filaments driven with symmetrical parallel electrodes. Physical mechanisms underlying the transient process are discussed.