The characteristics of lightning corona sheath are of common concern in the lightning physics and lightning protection research. Using the spectra of two natural cloud-to-ground lightning including multiple return strokes recorded by a slit-less spectrograph, we investigated the electrical conductivity distribution along the radial direction of the channel. The results indicated that a high conductivity channel of above 10⁴ S/m existed within an average radius of around 1.8 cm and corresponded to the temperature of around 20,000 K. This finding reflects the characteristics of the current-carrying channel. The electrical conductivity decayed steeply to about 500 S/m with increasing radius and then decayed slowly. Based on these results, it was estimated that the corona sheath radii of the return stroke channel were around 3.34–19.10 cm. The corona sheath radius was positively correlated with the leader charge quantity and the apparent diameter of the corresponding leader channel. A wide corona-channel radius corresponds to an intense discharge.

雷电晕护套的特性是雷电物理和防雷研究中普遍关注的问题。使用无缝隙光谱仪记录的两个自然云对地闪电的光谱（包括多个回程），我们研究了沿通道径向方向的电导率分布。结果表明，高于10 ⁴的高电导率通道 S / m存在于平均半径约1.8 cm之内，对应于约20,000 K的温度。这一发现反映了载流通道的特性。随着半径的增加，电导率急剧下降至约500 S / m，然后缓慢下降。根据这些结果，估计回程通道的电晕鞘半径约为3.34–19.10 cm。电晕鞘半径与前导电荷量和相应前导通道的表观直径呈正相关。宽的电晕通道半径对应于强烈的放电。