| Autor: |
Chen, Huaifei, Chen, Weijiang, Wang, Yu, Xiang, Nianwen, Li, Kejie, Fu, Zhong, He, Hengxin, Xiao, Lilang |
| Předmět: |
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| Zdroj: |
Geophysical Research Letters; 11/16/2024, Vol. 51 Issue 21, p1-8, 8p |
| Abstrakt: |
High‐time‐resolved mapping results of two rare reactivation processes following a negative return stroke are discovered and analyzed. At first, the discharges prior to the reactivation process were dominated by positive discharges lasting for tens of milliseconds in a limited space in the vicinity of a decayed negative leader channel. The positive discharges produced no detectable electric field change. Then, negative discharges started and propagated along the decayed downward negative leader channels at a speed exceeding 106 m/s for a few microseconds and produced negative electric field changes. The analysis reveals that the processes are physically distinct from recoil leaders and side discharges in terms of propagation behaviors, electromagnetic characteristics, and time scale. The possible mechanisms of the processes are discussed. The observation suggests that the reactivation processes of the negative leaders may lead to subsequent return strokes. Plain Language Summary: A hot topic in lightning research is how extinguished leader channels are reactivated. In recent years, the process of recoil leader reactivating the decayed positive leader channel has been extensively discussed. However, the reactivation process of the negative leader channel is not yet well understood. This paper reports the observation results of two reactivation processes of decayed negative leader channels following a negative return stroke. The discharges prior to the reactivation processes developed continuously for several tens of milliseconds and were dominated by positive discharges. Then, negative discharges started and transferred negative charges to the decayed grounding stroke channel within tens of microseconds. We describe the fact that the process is a new discharge process that does not fall within the scope of recoil leader or side discharge. However, the negative reactivation process may lead to subsequent return stroke, which has a similar effect to the recoil leader. Key Points: Two reactivation processes of decayed negative leaders were triggered following a negative return strokePositive discharges prior to the reactivation process lasted for tens of milliseconds and produced weak VHF radiationsThe negative discharges propagated along decayed negative leader channels for a few microseconds and produced electric field change [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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