云地闪电回击通道不同阶段的输运特性

Transport characteristics of cloud to ground lightning return stroke channel at different stages

利用无狭缝高速摄谱仪获得云地闪电回击过程的光谱,通过光谱学上的谱线辨认以及利用光谱特征分析的基础上。依据闪电光谱线的波长、相对强度以及谱线相互之间的跃迁参数等信息,结合有关等离子体的研究理论,用氧的中性原子和多谱线法得到了云地闪电放电通道的温度,同时用光谱线的Stark加宽方法计算了通道内含有电子的密度;并在此基础上,计算了同一次云对地闪电不同回击的不同时刻的通道热导率以及热扩散系数。计算结果表明:利用已有的理论方法所得到的闪电通道的特性参数值都在研究结果的范围内;其中通道内的输运系数,即热导率和热扩散系数值的大小与等离子体的通道温度和电子密度有很大的关系,且输运系数随着时间变化呈现出一定的规律,其结果在合理范围内。

The spectrum of cloud to ground lightning return stroke process is obtained by using slit free high-speed spectrograph,which is based on spectral line identification and spectral characteristics analysis.According to the wavelength,relative intensity and transition parameters of lightning spectral lines,combined with the research theory of plasma,the temperature of cloud to ground lightning discharge channel is obtained by using neutral atom of oxygen and multi spectral line method,and the density of electrons in the channel is calculated by using Stark broadening method of spectral lines.On this basis,the same cloud to ground lightning discharge channel is calculated The channel thermal conductivity and thermal diffusion coefficient at different time of lightning return stroke.The calculation results show that:the characteristic parameters of lightning channel obtained by the existing theoretical methods are within the range of the research results;the transport coefficient in the channel,that is,the thermal conductivity and thermal diffusion coefficient,has a great relationship with the channel temperature and electron density of the plasma,and the transport coefficient changes with time in a certain law,and the results are in a reasonable range Inside.