为了研究带有沿面放电的点线四边形斑图的形成,采用空气一氩气介质阻挡放电装置,在降压过程中首次观察到了带有沿面放电的点线四边形斑图,该斑图由带线亮点、不带线亮点和连线构成,且连线构成的四边形结构与斑图成45°。斑图的演化经历了4个过程:类六边形斑图、带有沿面放电的点线四边形斑图、格子四边形斑图和随机放电丝。采用高速录像机对该斑图进行短曝光录像,发现连线是由带线亮点的沿面放电形成的。采用光电倍增管对斑图中不同位置放电丝的光信号进行采集,发现亮点在电压上升沿和下降沿都有放电,且在上升沿是多次放电,在下降沿放电是带连线亮点先于不带连线的亮点。利用发射光谱法,研究了斑图中不同亮点的分子振动温度和电子密度,计算结果得知:分子振动温度是带线亮点小于不带连线亮点,而电子数密度却相反。最后讨论了极板表面不同区域积累的壁电荷量对此斑图的形成及其时空动力学行为的影响。
In order to study the formation of a dot-line square pattern with surface discharge, the pattern is observed for the first time in air-argon dielectric barrier discharge with the applied voltage decreasing. The dot-line square pattern is composed of lines and spots (spot with line and spot without line), and the square structure connected by lines and the pattern into 45°. The discharge undergoes the quasi hexagonal pattern, a dot-line square pattern with surface discharge, grid square pattern and random filaments as the applied voltage decreases. A high-speed video camera was used to obtain a short exposure time images for the dot-line square pattern. It was found that the line was formed by surface discharge of bright spots. The spatio-temporal dynamics of the dot-line square pattern were measured by the photomultiplier, and the results showed that the bright spots had discharge in the voltage rising or falling and rising along with multiple discharge, and the spot with line discharge was ahead of the spot without line in the falling. The method of emission spectrum was used to study the molecular vibration temperatures and electron density of different spots in this pattern. Measurements showed that molecular vibrational temperature of spot with line was less than spot without line, while the electron density was the opposite. Finally, the influence of wall charge distribution on the forming process and the spatio-temporal dynamics of the dot-line square patterns was discussed.