From one to many: Do characteristics of dielectric barrier discharges scale with the number of filaments?*

The formation and interaction of individual filaments in dielectric barrier discharges (DBDs) are essential for the efficiency and efficacy of DBD reactors used in various applications. In most DBD arrangements, multiple filaments are formed, since the power input per filament is limited.

Therefore, the impact of external parameters (like N₂/O₂ ratio of the working gas or characteristics of the applied high voltage (HV), e.g. pulsed vs. sinusoidal) on the number of filaments per period and their ignition pattern is studied. 

The spatially 1D multi-filament arrangement had a length of about 10 mm while the gap distance was set to 1.0 mm. The working gas was a binary mixture ranging from 0.1 to 20 vol% O₂ in N₂ at 1 bar.

The DBDs were characterised by iCCD camera imaging determining the filament number and the discharge development by a streak camera to obtain the filament positions during different phases of one HV period, while measurements using fast probes were simultaneously performed. 

The results clearly show the different effects of the performed parameter variations on pulsed and sine-driven discharges, particularly regarding the spatial stability and number of filaments. Finally, the findings for the multi-filament arrangement are linked to single-filament DBDs under the same experimental conditions.