中文摘要：

大气压低温等离子体富含高活性粒子，在生物医学、薄膜沉积、环境治理等领域表现出巨大的潜在应用价值。为此，针对不同频率正弦交流电压下大气压氦气平行平板型介质阻挡放电（DBD），开展其放电行为和基本特性的研究，包括放电电流峰值、放电功率、气隙的首次和稳态击穿电压、发射光谱及其微秒放电图像。研究发现：随着频率的增加，更易获得稳定均匀的HeDBD，同时，稳态击穿电压略有下降，首次击穿电压则有所提升；当驱动频率高于一定值时，DBD出现了正负放电不对称和倍周期等非线性行为。进一步对微秒曝光图像和发射光谱的研究表明：在10—90kHz范围内，HeDBD均为大气压辉光放电：与激发态N2和N2^＋相比，激发态OH谱线强度随着频率具有明显的增长趋势。

英文摘要：

Atmospheric pressure low temperature plasma is rich of active species and has potential application value in different fields. In this paper, the electrical and optical characteristics of atmospheric pressure parallel plate dielectric barrier discharge （DBD） in helium, including the discharge current peak, discharge power, first breakdown voltage, stable breakdown voltage, emission spectrum and discharge images, are studied by changing the applied voltage frequency. It is found that stable uniform discharge is easier to be produced with higher applied voltage frequency. When applied voltage frequency increases, the stable and first breakdown voltages decrease and increase slightly, respectively. Some nonlinear phenomenon appears in He DBD under some special applied voltage frequencies. By taking discharge images （exposure time -μs） and optical spectra, it is found that the He DBD presents to be glow discharge in the range of 10-90 kHz; the line intensity of excited OH increases more obviously than that of excited N2 and N2^＋.