The time-resolved spectra of four ultrashort-path cloud lightning were taken by a high-speed slit-less spectrograph. Based on the spectra, the temperature, electron density, and development characteristics of the ultrashort-path cloud lightning channels were investigated for the first time. For these four ultrashort-path cloud lightning, the minimum length of the channel in the horizontal direction is approximately 130 m and that in the vertical direction is approximately 50 m. The average development velocity of their leader is 10–10 m/s. Intense ionic lines with high excitation energies radiated at the initial stage of the leader. When the entire channel formed, no intense pulse of light radiation with high excitation energy (ionic lines) occurred, such as the return stroke of cloud-to-ground (CG) lightning. That is, high charge density appeared at the initial moment of the leader, indicating that there may be a strong energy pulse during the initial stage of the leader. The temperatures of the channel near the cloud base, the initial and terminal ends are higher than those at other positions. According to the spectral characteristics, the current of ultrashort channel cloud lightning should be much smaller than that of normal cloud and CG lightning. It is inferred from the development of ultrashort-path cloud lightning, the range of cumulonimbus clouds with opposite charges over the plateau mountainous region should be much smaller than the typical values in other regions.

中文翻译：

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超短程云闪电通道的发育及热力学特性

高速无缝摄谱仪拍摄了四个超短路径云闪电的时间分辨光谱。基于光谱，首次研究了超短程云闪电通道的温度、电子密度和发展特征。对于这4次超短路径云闪电，通道的水平方向最小长度约为130 m，垂直方向最小长度约为50 m。他们的领导者的平均发展速度是10-10 m/s。在先导的初始阶段辐射出具有高激发能的强离子线。当整个通道形成时，没有发生具有高激发能量的强光辐射脉冲（离子线），例如云对地（CG）闪电的返回。即先导初始时刻出现高电荷密度，表明先导初始阶段可能存在较强的能量脉冲。通道靠近云底、始端和末端的温度均高于其他位置。根据光谱特征，超短通道云闪电的电流应远小于普通云和地闪的电流。从超短程云闪电的发展情况推断，高原山区上空异电荷积雨云的范围应远小于其他地区的典型值。