Development of an analytical model for nonthermal atmospheric barrier discharges

Diffuse nonthermal atmospheric gas discharges generated between two dielectrically coated electrodes (dielectric bar-rier discharges) are particularly attractive for many materials processing applications largely due to their significant practi-cality afforded by the removal of the vacuum system, Their potentials for a wide range of industrial and medical applica-tions have been copiously demonstrated in many application studies in literature. By contrast, their fundamental under-standing is relatively weak at present and there are compa-rably fewer studies focusing on the generic characteristics of nonthermal atmospheric gas discharges. Development of vi-able theoretical tools will improve our current understanding of generic plasma behaviors, as well as expedite the develop-ment of better nonthermal atmospheric plasma sources. It has been shown that electrical features, particularly the voltage-current characteristics, of nonthermal atmospheric di-electric barrier discharges can be well reproduced using sim-plified fluid models based on the hydrodynamic approxima-tion. In this contribution, we report our development of a further simplified theoretical tool. This is based on an an-alytical model for diffuse nonthermal atmospheric discharges in a single-component noble gas. Space charges are taken into account. We demonstrate that though kinetic effects are ig-nored the developed analytical model can predict accurately the evolution of the discharge current density and the electric field. In particular we show that the waveform of the discharge current pulse is predominately determined by that of the applied voltage and that its peak value is strongly in-fluenced by the temporal variation of the ion drift velocity. Such an analytical model of nonthermal atmospheric dielectric barrier discharges offers mathematical simplicity and physical clarity that are often crucial in gaining physical insights and deducing scaling laws. It should be a simple first-stop tool to develop basic understanding of discharge dynamics under dif-ferent operation conditions (e.g. gas composition and applied voltage) as well as evolve new and different operation schemes of nonthermal atmospheric gas plasmas before embarking on full-scale experimentation or/and numerical simulation.