介质阻挡放电中不同厚度气隙内微放电通道的光谱特性研究

采用发射光谱法，研究了具有三层介质的介质阻挡放电中不同厚度气隙内微放电通道的等离子体参量的变化规律。与在传统的具有双层介质的介质阻挡放电系统中所产生的微放电通道不同，三层介质系统内微放电通道在光谱特性方面展现了完全不同的性质以及变化规律。实验发现，微放电通道在不同的放电气隙中具有不同的发光强度。利用氮分子第二正带系(C3Π_u→B3Π_g)的发射谱线以及对氮分子离子391.4 nm谱线强度与氮分子394.1 nm谱线强度之比的考察，实验进一步测量了氮分子(C3Π_u)的振动温度以及电子平均能量分别随氩气含量以及在不同电压下的变化规律。结果表明，当外加电压一定时，厚气隙内形成的微放电丝在分子振动温度以及电子平均能量上均低于薄气隙微放电丝。并且它们都随着氩气含量的增加而降低。随着电压的逐步升高，厚气隙内的微放电丝在以上两种参量上均基本保持不变，而薄气隙内微放电丝则出现较为明显的升高。这表明具有三层介质的介质阻挡放电中薄气隙较厚气隙对电压更为敏感且在相同电压浮动内电场变化范围更大。

Study on Spectral Characteristics of Micro Plasma Channels of Different Gas-Gap in Dielectric Barrier Discharge

By optical emission spectrum, we report on the first investigation on the plasma parameters of micro plasma channels which are generated in two gas-gaps with different thickness in a triple-layer dielectric barrier discharge system. Different from the micro plasma channels formed in traditional two-layer dielectric barrier discharge, micro plasma channels formed in the triple-layer dielectric barrier discharge system reflect a unique discharge characteristic. From the pattern images taken by an ordinary camera, it shows that micro plasma channels generated in two discharge gas-gaps discharge with different sizes and light intensities. The micro plasma channels in wide gas-gap are much bigger than those in narrow gas-gap, and their light intensities are obvious stronger. By collecting the emission spectra of N₂ second positive band (C3Π_u→B3Π_g) and calculating the relative intensity ratio method of N₂ molecular ion line at 391.4 and the N₂ molecular line at 394.1, the molecular vibration temperature and the average electron energy of micro plasma channels in two gas-gaps as functions of Argon concentration and applied voltage are investigated, respectively. It is found that the molecular vibration temperature and the average electron energy of micro plasma channels in wide gas-gap are lower than those in narrow gas-gap, and they both decrease with the increasing of the Argon concentration. As the applied voltage increases, micro plasma channels in wide gas-gap vary in a small range on the above two plasma investigations, while those in narrow gas-gap vary obviously. It indicates that micro plasma channels in narrow gas-gap are more sensitive to the applied voltage and they have a wider variation range of electric field than those in wide gas-gap.