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Description
The arrival time distribution of secondary particles from an extensive air shower is one of the important parameters to reconstruct the information of primary particles. Due to the acceleration/deceleration and deflection by the thunderstorm electric field, the number and space-time of the ground-level particles are altered, resulting in a variation of the shower detection and reconstruction. In this work, the temporal structure of secondary particles is studied by analyzing the KM2A data in 2022. The arrival time variation is found to be correlated to the thunderstorm electric fields, and the lightning flashes. During a thunderstorm, the arrival time distribution becomes wider, and the change amplitude is not only dependent on the electric field strength, the core distance, and also strongly dependent on the primary zenith angle. The particle flux variations within different time windows during thunderstorms are also studied. Our results are useful in understanding the change of shower rate detected by KM2A, and will also provide important information for shower reconstruction during thunderstorms.
