Wang Jie, Yuan Ping, Zhang Hua-ming, Shen Xiao-zhi
College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2008 Sep;28(9):2003-8.
According to the wavelengths, relative intensities and transition parameters of lines in cloud-to-ground lightning spectra obtained by a slit-less spectrograph in Qinghai province and Xizang municipality, and by theoretical calculations of plasma, the average temperature and electron density for individual lightning discharge channel were calculated, and then, using Saha equations, electric charge conservation equations and particle conservation equations, the particle densities of every ionized-state, the mass density, pressure and the average ionization degree were obtained. Moreover, the average ionization degree and characteristics of particle distributions in each lightning discharge channel were analyzed. Local thermodynamic equilibrium and an optically thin emitting gas were assumed in the calculations. The result shows that the characteristics of lightning discharge plasma have strong relationships with lightning intensities. For a certain return stroke channel, both temperatures and electron densities of different positions show tiny trend of falling away with increasing height along the discharge channel. Lightning channels are almost completely ionized, and the first ionized particles occupy the main station while N II has the highest particle density. On the other hand, the relative concentrations of N II and O II are near a constant in lightning channels with different intensities. Generally speaking, the more intense the lightning discharge, the higher are the values of channel temperature, electron density and relative concentrations of highly ionized particles, but the lower the concentration of the neutral atoms. After considering the Coulomb interactions between positive and negative particles in the calculations, the results of ionization energies decrease, and the particle densities of atoms and first ionized ions become low while high-ionized ions become high. At a temperature of 28000 K, the pressure of the discharge channel due to electrons, atoms and ions is about 10 atmospheric pressure, and it changes for different lightning stroke with different intensity. The mass density of channel is lower and changes from 0.01 to 0.1 compared to the mass density of air at standard temperature and pressure (STP).
根据青海省和西藏自治区使用无狭缝光谱仪获得的云地闪电光谱中谱线的波长、相对强度和跃迁参数，以及等离子体的理论计算，计算了单个闪电放电通道的平均温度和电子密度，然后利用萨哈方程、电荷守恒方程和粒子守恒方程，得到了各电离态的粒子密度、质量密度、压力和平均电离度。此外，分析了每个闪电放电通道中的平均电离度和粒子分布特征。计算中假设了局部热力学平衡和光学薄发射气体。结果表明，闪电放电等离子体的特征与闪电强度有很强的关系。对于某一回击通道，不同位置的温度和电子密度沿放电通道随高度增加均呈现微小的下降趋势。闪电通道几乎完全电离，首次电离的粒子占主导地位，而N II的粒子密度最高。另一方面，在不同强度的闪电通道中，N II和O II的相对浓度接近常数。一般来说，闪电放电越强，通道温度、电子密度和高电离粒子的相对浓度值越高，但中性原子的浓度越低。在计算中考虑正负粒子之间的库仑相互作用后，电离能结果降低，原子和首次电离离子的粒子密度降低，而高电离离子的粒子密度升高。在28000 K的温度下，由电子、原子和离子引起的放电通道压力约为10个大气压，并且对于不同强度的不同闪电回击会有所变化。与标准温度和压力（STP）下空气的质量密度相比，通道的质量密度较低，在0.01至0.1之间变化。
