光記録システムによる雷放電電流の実測と解析

Abstract

The authors have developed the portable high-resolution computerized optical systems with a sampling period of 100ns and a recording time of 6.5ms. By using the systems, a 35kA-class positive lightning current was measured. The obtained waveform consists of many current peaks. The frequent repeated discharges of below 1 C and the middle ones above 1 C appear in the early stage (0.4-1ms) and in the grown period (1-2ms) respectively. The rest of the waveform shows a serial discharge current of about 30kA till the time of 5.8ms when the current becomes to decrease.