Publication Date:
2018-09-06
Description:
Waveforms of vertical electric field observed at distances of 27, 57, and 101 km from the 634-m tall Tokyo Skytree (Japan) struck by lightning have been reproduced using the 3-D finite difference time domain method. Optically observed 3-D lightning channels and currents directly measured in the tower were used. Distribution of current along the lightning channel was represented using the transmission line model, assuming a constant propagation speed v = 0.5c. Simulations with commonly assumed vertical channel did not allow us to reproduce the observed early (within 5 μs or so) field zero crossing when the 1-D speed was set to be constant and equal to the 3-D speed (v = 0.5c) used for the actual-channel-geometry case. It was, however, possible to achieve a good match for a vertical channel when the vertical component of 3-D speed was evaluated for each nonvertical channel segment and used in the corresponding range of heights. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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