利用H_α谱线Stark加宽研究闪电放电通道的电场和电流

Study on the electric field and current of lightning channel by Stark-broadening

依据等离子体电场强度的诊断方法,得到了Hα线Stark加宽与闪电放电等离子体电场强度的关系;同时利用Borovsky定理对放电通道电场分布的分析及广义欧姆定律,得出了闪电放电通道表面径向电场与通道内垂直电场及电流强度的关系,并分析了青海地区用无狭缝高速光栅摄谱仪获得的一次云对地闪电回击过程中光谱Hα线的Stark加宽,对通道不同位置的电场和电流进行了定量计算,得到了该放电通道表面附近径向方向电场为5.49×104~6.84×104 kV·m-1,通道中电场垂直分量为3.29~4.10kV·m-1,电流强度为28.98~36.04kA.结果表明,通道表面附近的径向电场远大于通道垂直电场,且随着通道位置的升高,电流及沿通道垂直方向的电场强度均减小.

According to Griem＇s method of diagnosis electric field in plasma,the relationships between the Stark-broadening of line and the electric field of lightning plasma are obtained.Meanwhile,using the analysis of electric field distribution in lightning discharge channel performed by Borovsky and the generalized Ohm＇s law,the relationships between the radial electric field near the channel and the vertical electric field in the channel,and between the radial electric field near the channel and the current are derived.On the basis of above relationships and using the spectrum of lightning plasma,the electric field and the current at lightning different channel height are calculated.The results show that the radialelectric fields near the channel are in the range of 5.49×104~6.48×104 kV·m-1;the vertical electric fields are in the range of 3.29~4.10kV·m-1;the currents are in the range of 28.98~36.04kA;the radial electric field near the channel is more stronger than that the vertical electric field;the current and the vertical electric field decrease with increasing channel height.