Temperature Distribution And Evolution Characteristic In Lightning Return Stroke Channel

Research on lightning physical process and mechanism is the theory basis for lightning warning and protection work. Observation of lightning spectrum is an effective way to obtain the physical parameters of the lightning channel. This thesis mainly analyzes the high time-resolved spectra of four cloud-to-ground lightning return stroke processes captured by the recording equipment of self-modified high-speed slit-less spectrograph in Qinghai Plateau. The temperatures of arc core current channel and the peripheral optical channel surrounding the arc core are investigated by different methods, the time evolution of the temperature during the current delay stage and the temperature distribution along the radial direction of the channel on the peak current stage are discussed. The results show that the temperature of arc core channel is about 4000-5000 K higher than that of the peripheral optical channel, and a temperature gradient is formed along the radial direction of channel during the discharge process. With the increasing of the radius, the temperature decreases gradually. The time evolution of channel temperature shows that the falling of the temperature is very slow compared with the decreasing of the current after their peak values. Up to 200-400 ?s after the peak current, the channel temperature is still maintained at around 20000 K. The heat effect resulting from such a long-time high temperature is the main source of most direct lightning disasters.