为了深入探究纳秒脉冲电源作用下沿面介质阻挡放电等离子体特性参数的演化规律,揭示其作用机理,文中搭建了纳秒脉冲电源作用下非对称结构沿面介质阻挡放电等离子体光电特性实验测量平台,并在此基础上建立了放电集总参数等效电路模型,通过对比实验推理和仿真计算分别得到的放电电流以及电子密度参量,证明了模型的有效性。文中通过该模型计算得到了介质表面电压、气隙电压以及电子温度等等离子体特性参数随时间的变化关系,并进一步研究了电源斜率对大气压沿面介质阻挡放电电流的影响。得到的主要结论为:单极性纳秒脉冲电源作用下,在脉冲上升沿存在二次放电,在下降沿存在反向放电过程,电子温度与电子密度高达8.3 e V和2.7×10^(18)m^(-3),电源斜率对放电有重要的影响,随着电压上升率增加,第1次放电的电流增大。放电时刻提前,但是对应的第2次放电电流略有减小,下降率的增加则对应着第2次放电电流幅值的增加,第1次放电的电流则略有减小,研究结果为深入分析激励器放电特性,提高等离子体发生器效率提供参考。
A study of the evolution of the pulse width in homogeneous dielectric barrier dis- charge at atmospheric pressure with helium as the working gas is reported by using a one- dimensional fluid model. In this paper, a new computational method is presented to estimate the pulse width through calculating the time interval between the breakdown voltage and the extinguishing voltage. The effects on the discharge characteristics of the applied voltage and exci- tation frequency are studied based on the computational data. The results of the simulation show that the pulse width is observed to be narrower and the time intervals between two consecutive current pulses decrease with increasing amplitude and excitation frequency, which indicates that the homogeneous discharge is susceptible to the filamentary mode. The simulation results support the conclusion that in order to restrain the transition from the glow mode to filamentary mode, the applied voltage and excitation frequency should be kept within an appropriate range.
