Dependence of Filaments Formations on Gas Temperature in Atmospheric Pressure Oxygen Dielectric Barrier Discharges

Since Siemens
¹
have been reported the dielectric barrier discharges (DBDs) in 1857, DBDs have been widely investigated, but the details of filament formations in DBDs, such as hexagonal, square
²
, self organization, quincunx
³
and so on, have not been clarified yet. Especially DBDs under atmospheric pressure, filament formations are occurred in nano second time scale, so it is very hard to measure the characteristics of DBDs. In DBDs, many conditions are affected in complex each other, secondary electron emission, accumulated charges, gas pressure and gas temperature, for example. Among the many conditions, gas temperature is one of the key conditions for filament formations. In this paper, the effect of gas temperature on filament formations have been investigated in atmospheric pressure oxygen DBD using a two dimensional fluid model
⁴
. And the simulations are calculated with considering of gas temperature increase and without. The simulations have been performed with the conditions in ref.[4]. In the case with considering gas temperature, self-organized filament formation is obtained. In this discharge, filaments are formed by streamers with surface discharges. The filaments are formed at the same places in sequence cycles of discharges. And the case without considering gas temperature, quincunx filament formation is obtained. Many isolated high electron density regions are formed in the vicinity of the dielectrics and the regions are formed on each side of dielectric in staggered in each half cycles. And it is found that the discharge development in this discharge is so-called glow-like discharge. And the surface discharges are not occurred in this case. In both cases, the maximum electron densities obtained lower than normal DBDs, and the electron density in quincunx case obtained in lower than self-organized case. As a result, it is found that gas temperature would affect on discharge development and then the filament formation and structures.