NI 493.5 nm谱线Stark加宽估算闪电放电等离子体电子密度

Calculation of Electron Density for Lightning Discharge Plasma by NI 493.5 nm Line Stark Broadening

依据青海地区一次闪电回击过程的光谱,分析了NI 493.5 nm谱线的Stark加宽效应,得到加宽在1.5-2.5 nm左右,通道不同位置的谱线两边显示出稍有一些不对称性;结合NI 493.5 nm线Stark加宽的半经验参数,对通道不同位置的电子密度进行了定量计算,得到平均电子密度是1.657×10^17cm^-3,并与各位置处用Hα谱线半宽得到的电子密度进行了比较,证实用NI 493.5 nm和Hα谱线半宽得到的电子密度基本一致,由NI谱线的Stark加宽估算闪电等离子体电子密度是一种实用可信的方法。数据分析表明：随着通道位置的升高,电子密度略呈减小趋势;电子密度与谱线半宽近似呈线性关系。

According to one spectrum of lightning return stroke in Qinghai Province, it is show that the Stark broadening are about 1.5-2.5 nm and the NI 493.5 nm lines at different positions within the channel present slight asymmetry after analyzing the Stark broadening effect of NI 493.5 nm line. The electron densities at different positions of the channel have been calculated combining with semi-empirical parameters of NI 493.5 nm lines Stark broadening, and the average electron density at 1. 657 × 10^17 cm^-3 is further obtained. After comparing the electron densities obtained from NI 493.5 nm and Ha lines at different positions within channel, we confirm that the electron densities obtained from NI 493.5 nm and Ha lines are approximately same, and it is a creditable and practical way for calculation of eletron density by NI 493.5 nm lines Stark broadening. The result reveals that the electron densities show a tiny trend of becoming low with increasing of height along the channel. Besides, the electron densities exhibit a nearly linear dependence on the half-widths of NI 493.5 nm lines.