Symmetric self-organized discharge filaments have been observed in the 140-µm-microgap dielectric barrier discharge between two parallel glass plates. Images of the discharge in microseconds were obtained using an intensified charge-coupled device (ICCD) camera. The diameters of these self-organizing filaments, the distance between the filaments, and the approximate speed of the moving filaments were obtained using the ICCD images.Index Terms-Dielectric barrier discharge (DBD), intensified charge-coupled device (ICCD), microgap, plasma photonic crystal (PPC), self-organization. P LASMA photonic crystals (PPCs) have been obtained by the self-organization of filaments in an atmospheric dielectric barrier discharge (DBD), which has attracted significant attention from researchers [1]. PPCs not only have a photonic bandgap (which intercepts a specific electromagnetic wave) and negative refraction but also have dynamic controllability. In PPCs, it is important to determine the diameters of the selforganizing filaments, the distance between filaments, and the electron density of the filament, because the bandgap depends greatly on the structure of the self-organizing discharge pattern. In this paper, the transition of the atmospheric self-organized DBD plasma in submicrometers is investigated using an intensified charge-coupled device (ICCD) camera.The microgap consists of two glass plates, each of which is 5 mm wide, 20 mm long, and 0.4 mm thick. An indium tin oxide (ITO) film is evaporated on the glass plates and used as a transparent electrode for the visible light emitted by the discharge. The distance between the two dielectric glass plates was set to 140 µm. The upper ITO-evaporated glass plate was used as a powered electrode and was connected to a 100-kHz-RF power source. The lower ITO-evaporated glass plate was connected with grounding. The applied voltage was between 570 and 963 V. Helium gas was fed into the gap between the two parallel glass plates through a mass flow controller. The helium gas velocity was between 1.1 and 88.9 m/s. Images of the discharge were photographed with a digital camera (exposure time: 500 µs) and an ICCD camera (exposure time: 100 µs).

In this paper, we present subsequent images of self--organized filaments in a microgap atmospheric barrier discharge with and without bismuth silicon oxide (BSO) dielectrics. The images were obtained using an intensified charge-coupled device digital camera. Different developments of the discharge were observed in the region occupied by the filaments in the case of BSO and glass dielectrics. The charge distribution on the dielectric surface played an important role in the development of the self-organized patterns.Index Terms-Bismuth silicon oxide (BSO), dielectric barrier discharge, helium, microgap discharge, self-organized discharge.

No abstract