大气压脉冲调制射频放电中相关时间尺度效应的数值模拟

Numerical study on the time-scale effects of atmospheric pulse-modulated radio frequency discharges

近年来,大气压射频放电由于可以产生大体积均匀的等离子体而引起人们极大的关注,引入脉冲调制后,所产生的脉冲调制等离子体与连续等离子体相比表现出不同的放电行为,这为研究大气压射频放电中不同的时间尺度关系提供了条件。本文基于一维流体模型,以首电流脉冲为研究对象,研究了电压变化时间(射频频率)、电压施加时长和电压关断时长对放电的影响,讨论了电场变化、带电粒子迁移与带电粒子扩散之间不同时间尺度的关系。计算结果表明,首电流脉冲现象仅出现在电压变化时间较短,即电压变化率较高的条件下;随着电压施加阶段的延长,首电流脉冲将明显增强,稳定后的放电电流也有所增加;随着电压关断阶段的延长,首电流脉冲先增强后减弱,稳定后的放电电流则一直减小。本文的研究有助于深刻理解大气压射频放电中不同时间尺度之间的关系,为实际应用中放电参数的选择提供理论依据。

In recent years,atmospheric pressure radio frequency discharge has attracted extensive attention because of its advantages in producing large volume uniform plasma.Compared with continuous plasma,the plasma produced by pulse modulation showed different discharge behavior,which provided conditions for the study of different time scale relationships in atmospheric pressure radio frequency discharge.Based on the one-dimensional fluid model,taking the Peak Current in the First Period as the research object,this paper studied the effects of voltage rise phase duration(RF frequency),power-on phase duration and power-off phase duration on discharge,and discussed the relationship between different time scales of electric field change,charged particle migration and charged particle diffusion.The results showed that the Peak Current in the First Period only occured under the condition of high voltage rise rate;With the increase of power-on phase duration,the Peak Current in the First Period will increase significantly,and the discharge current after stabilization will also increase;With the increase of power-off phase duration,the peak current in the first period first increased and then decreased,and the discharge current after stabilization decreased all the time.The research of this paper was helpful to understand the time scale effect of atmospheric pressure pulse-modulated RF discharge,and provides a theoretical basis for the selection of discharge parameters in discharge application.