Study on rocket-triggered lightning in Indonesia

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The object of this research is to study the characteristics of lightning in tropical zone by cooperative experiment of rocket triggered lightning between Japan and Indonesia in Jawa island. Also it is expected that the reserch will promote the protection techniques for lightning damage to electric power and communication systems in Indonesia.The experiment site with rocket launchers and a hut for control and observation was built in tea field near Puncak pass in south of Jakarta. A small rocket was launched with grounded steel wire for thundercloud, then a lightning discharge was triggered after an upward leader stroke was launched from the tip of rocket wire. The lightning current and wave shape were measured by memory devices. The induced voltages at ground and on test power line were obtained with the photograph of discharge.The total of successful triggerings since 1990 in Puncak experiments is 15 including 4 of 1994-1995. The polarity of discharge currents is negative expect one of positive. It is similar to summer lightning in Japan. A half of discharges is small current of less than 1.5KA,which is a feature of artificially triggered lightning. Another half is big current of 9.8kA in average and the maximum of 15KA.The wave shapes are similar to the standard lightning impulse wave with 1-10mus of front and 50 MS of half tail. Another appreciated result was obtained three times in the triggered discharge to a lightning rod as a protection phenomenon for lightning damage.