中文摘要：

为降低气体的击穿和维持电压，设计一种螺旋针-环电极结构的等离子体射流装置，研究不同电压下的放电电压、电流波形。研究表明，氦气等离子体射流放电可以分为电晕放电、介质阻挡放电和射流放电三个阶段，并且可以通过放电电压、电流波形的特征进行区分。分析可知，射流管管径较大时，采用螺旋针状内电极结构可以减小电极间的平均气体间隙距离，从而降低气体的击穿和维持电压，使放电更加容易进行；电压反向过程中残留电荷使得合成电场得到加强，气体将“提前”发生放电；由于电极结构的不对称，气体在正半周期更容易发生放电，放电产生的电流脉冲数目更多，电流值更大；随着外加电压增大至14kV，放电最终过渡到丝状放电状态。

英文摘要：

To reduce the breakdown and maintenance voltages of the gas discharge,a plasma jet device with spiral needle-ring electrodes was designed.The discharge voltage and current waveforms under different voltages were studied.It is shown that helium plasma jet discharge can be divided into three stages,including corona discharge,dielectric barrier discharge and plasma jet discharge,which can be distinguished according to the characteristics of the discharge voltage and current waveforms.The spiral needle-ring structure can reduce the average gas gap distance between electrodes,thereby reducing the breakdown and maintenance voltages of the gas discharge,making the discharge easier.Residual charge in the process of the voltage reverse increases the synthetic electric field,so that the discharge is easier to start.Due to the asymmetric electrode structure,gas is more prone to discharge in the positive half cycle.The discharge eventually develops to filamentary discharge as the applied voltage increases.