MEASUREMENT OF LIGHTNING STROKE CURRENT AT IRUKAIKE - OPTICAL FIBER CABLE SYSTEM.

An attempt to measure the lightning stroke current near Irukaikec is described. A rocket with a wire was fired toward a thunder cloud to trigger the lightning stroke. In order to measure the lightning stroke current, an optical fiber cable system using an optelectronic conversion device was applied. This system is not influenced by the static and magnetic inductions caused by a lightning stroke. The number of heavy thunder storms coming just above our station in this year was smaller than that in a normal year. Four rockets were fired, but no lightning strokes were triggered. The results of the preliminary experiment in the laboratory, the circuit used for the actual measurement and the problems which remain unsolved are discussed.