Exploring the mechanisms leading to diffuse and filamentary modes in dielectric barrier discharges in N$$_2$$ with N$$_2$$O admixtures

Abstract

The effects of nitrous oxide (N$$_2$$ 2 O) in nitrogen (N$$_2$$ 2 ) on the development and morphology of sine-driven dielectric barrier discharges in a single-filament arrangement were studied. Detailed insight in the characteristics of the discharge and its development were obtained from electrical measurements combined with ICCD and streak camera recordings as well as numerical modelling. A miniaturised atmospheric pressure Townsend discharge (APTD) could be generated for admixtures up to 5 vol% N$$_2$$ 2 O in N$$_2$$ 2 although N$$_2$$ 2 O is an efficient collisional quencher of metastable nitrogen molecules. Increasing the high voltage amplitude led to a transition into a hybrid mode with the generation of an intermediate filament in addition to the diffuse, non-constricted APTD. A time-dependent, spatially one-dimensional fluid model was applied in order to study the underlying mechanisms causing the diffuse discharge characteristics. It was found that even for small N$$_2$$ 2 O admixtures, the associative ionisation of atomic nitrogen and oxygen (O + N($$^2$$ 2 P) $$\rightarrow $$ → NO$$^+$$ + + e) is the major electron source sustaining the volume memory effect and is therefore the reason for the formation of a diffuse APTD. Graphical abstract

Complex characterisation of Cr-doped α-Al 2O3 for DBD applications

“…This is similar to the transition from APTD mode to the filamentary mode shown in figure 18. Similar hybrid mode was discussed in [48]. The 'hybrid' mode was also observed for most of the other samples, however with a very weak APTD profile only compared to 5Cr or 3Cr.…”

Time-resolved investigations of a glow mode impulse dielectric barrier discharge in pure ammonia gas by means of E-FISH diagnostic

“…Over the last decades, non-thermal plasma developed with dielectric barrier discharge (DBD) cells has been extensively studied, for various fields such as biomedical applications [1][2][3], chemical fuel reforming processes [4,5], plasma actuators for high-speed flow control [6] or icing mitigation [7] and surface modifications [8][9][10][11]. These discharges expose three different operating modes [8,[12][13][14][15]: filamentary, diffuse (or also qualified as homogeneous) and patterned (or also named as self-organized). The filamentary discharge mode is characterized by a multitude of streamers, randomly distributed in time and space over the dielectric surface.…”