Investigation of instabilities and striation structures in single filament dielectric barrier discharges in argon at atmospheric pressure

利用数值模拟的方法，分析了大气压介质阻挡放电中条纹结构的形成机制和自发模式跃迁和不稳定性的物理原因。为此，将发展一个自洽的流体动力学等离子体模型，用于描述大气压下单丝介质阻挡放电的时间和空间二维特性，并用于研究在所考虑的放电中实验观察到的现象。特别是，将阐明哪些物理过程导致实验观察到的放电模式的形成和沿放电通道的条纹的发生。此外，还分析了氧混合气体对放电特性的影响。新的电子漂移-扩散近似和已建立的动力学方法的应用使得首次有可能研究大气压介质阻挡放电中非局域电子能量输运对产生条纹的影响。该项目的主要目标是通过基于实验分析设计的参数研究，更深入地了解外部放电参数，如电压幅值和频率的影响，以及气体杂质对放电稳定性的影响。有了这一点，就有可能优化输入参数，控制不同的放电模式，使它们可用于应用。

In the planed project the formation mechanisms of striated structures and the physical reasons for spontaneous mode transitions and instabilities in dielectric barrier discharges at atmospheric pressure are analysed by means of numerical modelling. For this, a self-consistent hydrodynamic plasma model for the temporal and spatially two-dimensional description of a single filament dielectric barrier discharge in argon at atmospheric pressure will be developed and applied for the investigation of phenomena observed experimentally in the discharge under consideration. In particular, it will be clarified which physical processes are responsible for the formation of the experimentally observed discharge modes and the occurrence of striations along the discharge channel. In addition, the influence of oxygen admixtures on the discharge characteristics is analysed. The novel drift-diffusion approximation for electrons developed previously and the application of established kinetic methods make it possible to study the effect of nonlocal electron energy transport on the generation of striations in dielectric barrier discharges at atmospheric pressure for the first time. The key objective of the project is to gain a deeper physical understanding of the influence of external discharge parameters, such as voltage amplitude and frequency, as well as the impact of gas impurities on the stability of the discharge by means of parametric studies based on a design of experiment analysis. With this, it becomes possible to optimize the input parameters, to control the different discharge modes and to make them usable for applications.