Effect on lightning electromagnetic fields from the return-stroke parameters

Choice of the return-stroke parameters has a great influence on the calculation results of lightning electromagnetic pulse(LEMP) fields. In this paper, LEMP fields under different return-stroke parameters are calculated based on the MTLL model in which the channel-base current is described by a pulse function. And effect of different return-stroke speeds and channel heights on LEMP fields of different field regions are also discussed. The results show that the lightning channel height between 1 kilometre and a few tens of kilometres has a little influence on the LEMP fields, but the return-stroke speed has a distinct influence on the LEMP fields.