Theoretical Study On The Spatio-temporal Dynamic Behavior Of Barrier Discharge At Atmospheric Pressure

In recent years, the plasma physics scientific community has paid much attention to the development of atmospheric pressure, non-equilibrium plasma sources. Progress in this field is very rapid. Dielectric barrier discharge (DBD) is one of the most important sources of low-temperature at atmospheric pressure, three discharge modes are often observed in this discharge systems, namely homogeneous mode, filamentary mode and pattern formation. The understandings of the spatio-temporal dynamic behavior in different modes are useful to product, stabilize and control the atmospheric non-equilibrium plasmas. In this dissertation, a fluid model with accelerated numerical algorithm is present to describe the spatio-temporal dynamic behavior of DBD at atmospheric pressure. The main DBD characteristics can be obtained from the model by analysis and numerical computation.The experimental and theoretical studies on the homogeneous DBD at atmospheric pressure, including atmospheric pressure glow discharge (APGD) and Townsend discharge, have been motivated by numerous potential discharge applications. In this dissertation, the one-dimensional form of our model is used to investigate the evolution of the differential conductivity in a whole half discharge period, and the existence of the negative differential conductivity is important to the homogeneous DBD. The effects on the discharge evolution have been discussed when the applied voltage varies and the high discharge current density always forms together with the narrow pulse-width. A two-dimensional numerical study is also completed in the dissertation to simulate the radial evolution of APGD, the simulation results are consistent with the experimental observations. For obtaining more uniform atmospheric low-temperature plasmas, the principle to eliminate the radial structure is also referred.DBD usually runs in the filamentary discharge mode. The discharge filament, namely the microdischarge channel, only lasts for several nanoseconds, and the position where the filament locates can not be predicted. The propagation of a single filament has been examined deeply according to the streamer theory. In this dissertation the two-dimensional theoretical investigation of the whole sptio-temporal behavior of filamentary discharge are present and the splitting and uniting of the filaments are also examined.