Abstract
Since 1986, the authors have been taking part in the triggered lightning experiments in winter, at the site of Okushishiku, Ishikawa, for the purpose of observing the entire lightning current waveforms with coaxial shunt resistors and an electrooptical measuring system. As the results, extra-fast current changes of the order of 1, 000 kA/μ s were recognized by the sharp pulse records superposed on the positive current waveform obtained by a shunt resistor of relatively high residual inductance. This was not the case with the resistor of lower inductance. Furthermore, a positive lightning current waveform which looks like the composite result of the bi-polar discharges has been observed by an advanced measuring system of high performance. This paper deals with those current-related topics of triggered lightning discharges to be analyzed hereafter in detail.
