2025-12-02 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/research_news/earth/202512/t20251203_1134400.shtml
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL117167
正極性雲対地雷撃における負極性リーダー上の横方向負極性再放電 Lateral Negative Re-Discharges on the Negative Leader in a Positive Cloud-to-Ground Lightning Flash
Zhuling Sun, Xiushu Qie, Fengquan Li, Mingyuan Liu, Lei Wei, Dongxia Liu, Chen Xu, Shanfeng Yuan, Chunfa Sun, Kexin Zhu, Ruiling Chen, Huimin Lyu, Yu Wang, Jinliang Li, YiXi QuZhen, Nima Chuduo
Geophysical Research Letters Published: 22 October 2025
DOI:https://doi.org/10.1029/2025GL117167
Abstract
Negative-polarity lateral discharges on pre-ionized negative channels during a positive cloud-to-ground lightning flash were captured by very high frequency interferometric observations. Prior to the return stroke (RS), as the positive leader (PL) advanced steadily and the negative leader (NL) weakened, flickering lateral re-discharges with small scale, resembling needles on PLs, propagated toward the NL tip at approximately 8.0 × 104 m/s. Unlike needles concentrated near PL tips, these re-discharges occurred along nearly the entire horizontal negative channel. Following the RS, both fast discharges along existing negative channels and new lateral discharges breaking into virgin air were observed, rapidly extending the negative channels and sustaining the continuing current. These re-discharges appeared to be closely linked to channel potential variations: gradual potential changes before the RS reactivation preceded negative branches, while abrupt potential jumps after the RS initiation triggered intense axial and lateral discharges.
Plain Language Summary
Lightning discharge remains a key focus in lightning physics study. Using a very high frequency lightning interferometer, we mapped a positive cloud-to-ground lightning flash over the Tibetan Plateau. Prior to the return stroke (RS), as the positive leader steadily advanced toward the ground and the negative leader (NL) weakened, small bursts of negative re-discharges repeatedly occurred on the pre-ionized NLs. Following the RS, two distinct types of new discharges emerged, some followed the existing paths, while others branched laterally into the surrounding air. All these discharges carried negative charges and were initiated by changes in electric potential along the lightning path. When the electric potential changed more quickly, the re-discharges were stronger and moved faster.
Key Points
- Very high frequency interferometer captured lateral negative re-discharges on pre-ionized negative channels in a positive cloud-to-ground lightning
- Lateral re-discharges spread along horizontal negative leader channels, unlike needles in a limited region near the positive tip
- Sustained positive leader growth and return stroke-induced potential changes triggered lateral extension of negative channels
