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

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 1.657×1017 cm-3 is further obtained.After comparing the electron densities obtained from NI 493.5 nm and Hα lines at different positions within channel,we confirm that the electron densities obtained from NI 493.5 nm and Hα 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.