Currents and radiated electromagnetic fields in lightning strikes to tall structures

Abstract

The paper presents recent developments in the study of lightning discharges - electrical transient components of a thunderstorm - striking elevated objects. In the computation of lightning return stroke currents, we analyze the disturbance introduced by the elevated strike object. A new methodology in lightning return strike modeling is proposed, and applied in the computation of lightning electromagnetic fields at far distances. We compared the resulting expressions with experimentally-measured lightning currents and electromagnetic fields observed at the CN Tower Research Center in Toronto, and found a reasonable agreement. The expressions can be used to calibrate the performance of lightning location systems in cases where lightning currents are measured directly on instrumented towers.