Differences in M‐components between triggered lightning striking the ground and overhead line

Abstract In the summer of 2018–2019, rocket‐triggered lightning experiments were conducted in Guangzhou, China. There were two types of lightning targets: ground and overhead line. By comparing the current and the electric field data in the two cases, it was found that when the continuous current level ( I CC ) and current amplitude ( I M ) of M‐components (current pulses generated during the continuous current stage) are large, the time difference between the electric field peak and the current peak ( T D ) will always be small. The rise time ( R T ) and half peak width ( T HPW ) of M‐components with high I CC and I M are low in both the cases. The threshold upper limit of T D in the case of lightning striking the ground is higher, approximately 2.6 times than that in the case of lightning striking the overhead line. We use an optimised guided wave model to simulate the electric field waveforms of M‐components. It was found that the shorter R T and T HPW of the M‐component, the smaller T D . The changes in wave speed and I M cannot affect the size of T D , and the impact of distance changes is very weak. The difference in the threshold upper limit of T D may be related to the significant difference in ground impedance in two cases.