This work aims to study the various parameters of LI (lightning impulse) discharge channels in an air gap, i.e., the reactive radicals, electron density and channel temperature, and the influence of water mist on the reactive radicals, electron density and channel temperature of the discharge using optical emission spectroscopy. During a LI discharge in air, the gas in the air becomes highly ionized, and the spectra of which are similar to reference spectra of natural lightning. The electron density and channel temperature of the discharges in air under a LI voltage is ca. $3\times 10^{23}\ \mathrm{m}^{-3}$ and ca. 13,000 K, respectively, both of which are lower than those of natural lightning. Compared with LI discharges in air, more OH and OH ⁺ radicals are detected when the discharge takes place in a water mist-air mixture, indicating the partial decomposition of water molecules on the surface of water droplets during the LI discharge. The addition of water mist results in an 8.8-10.7% lower electron density than during LI discharges in air. However, the addition of water mist does not obviously influence the channel temperature of the air discharge.

中文翻译：

---

有水雾和无水雾的长气隙雷电脉冲放电的发射光谱

本工作旨在研究气隙中 LI（雷电脉冲）放电通道的各种参数，即反应自由基、电子密度和通道温度，以及细水雾对气隙中反应自由基、电子密度和通道温度的影响。使用光发射光谱进行放电。在空气中的 LI 放电过程中，空气中的气体高度电离，其光谱类似于自然闪电的参考光谱。在 LI 电压下，空气中放电的电子密度和通道温度约为$3\times 10^{23}\ \mathrm{m}^{-3}$和约。分别为 13,000 K，均低于自然闪电。与空气中的 LI 放电相比，在水雾-空气混合物中放电时检测到更多的 OH 和 OH ⁺自由基，表明在 LI 放电过程中水滴表面的水分子部分分解。与空气中的 LI 放电相比，添加水雾导致电子密度降低 8.8-10.7%。但细水雾的加入对出风口的通道温度没有明显影响。