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May 14, 2019 Tuesday 03:20:00 PM IST

Why lightning strikes twice

Science Innovations

In contrast to popular belief, lightning often does strike twice, but the reason why a lightning channel is 'reused' has remained a mystery. The work by an international research team led by the University of Groningen has revealed that the negative charges inside a thundercloud are not discharged all in a single flash, but are in part stored alongside the leader channel at interruptions. This occurs inside structures which the researchers have called needles. These needles can have a length of 100 meters and a diameter of less than five meters, and are too small and too short-lived. Through these needles, a negative charge may cause a repeated discharge to the ground. The results clearly show the occurrence of a break in the discharge channel, at a location where needles are formed. These appear to discharge negative charges from the main channel, which subsequently re-enter the cloud. The results were published in the science journal Nature.

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