The Influence Of Lightning Leader Charge On Current Intensity And Spectral Characteristics Of Channel

The characteristic parameters reflecting the lightning return stroke discharge current intensity are one of the hot issues in the field of lightning physics research and protection.Due to the instantaneous feature of natural lightning,it is impossible to directly obtain the current waveform and gain the relevant physical parameters such as leader charge quantity.The charge quantity stored in the leader channel is a key factor affecting the return stroke discharge characteristics.The optical radiation characteristics revealed by spectral diagnosis can characterize the physical process of lightning plasma channels from a microscopic perspective,and study the influence of the leader charge on the return stroke current intensity and optical radiation characteristics.It can not only deepen the understanding of the microscopic physical process in the lightning discharge process,but also have important reference value for the development of lightning protection theory and technology.In this paper,based on the spectra taken in the lightning-prone area of Qinghai and the corresponding fast electric field change waveforms of cloud-to-ground lightning,part of the total charge quantity within the leader channel was estimated from different angles,and its influence on the peak current was studied.The results show that for the same lightning,part of the leader charge estimated from different angles based on the electric field change waveform is consistent with the charge quantity per channel length calculated based on the leader spectrum.Moreover,part of the neutralized leader charge is positively correlated with the peak current.This means that the discharge current intensity of the return stroke depends primarily on the charge quantity stored during the previous leader process.It is also found that when the front time is short,the return stroke current rises approximately in a straight line,and the leader charge is linearly correlated with the peak current.This indicates that the front time is one of the key factors affecting the leader charge and its correlation with the peak current.On this basis,the influence of part of the leader charge on the spectral characteristics in the channel is further analyzed.It is found that part of the neutralized leader charge is positively correlated with the total intensity of ionic lines and the radius of the core current-carrying channel in the return stroke spectrum,which further confirms that the intensity of the ion line in the spectrum can directly reflect the current intensity and is an ideal observable parameter for studying the current characteristics.It is also verified that the radius of the current carrying channel is a key parameter affecting the current intensity.