Electromagnetic Fields Generated by Lightning Channels with Tortuosity and Its Effect on the Time-of-Arrival Technique

In this paper it is presented a simulation analysis of electric fields generated by lightning channels with tortuosity. The tortuosity of the channel is reproduced by means of a numerical algorithm that takes into account statistical characterizations made by different authors observing real lightning channels, so the macroscale tortuosity of the simulated channel is similar to the one recorded in nature. Later it is used an analytic model which allows the calculation of the electromagnetic fields generated by lightning channels with tortuous geometries, once the geometry is known. The electromagnetic fields are calculated assuming a Heaviside step function as the current traveling along the channel. The objective of this work is to analyze two factors that could cause error in the time-of-arrival technique for lightning localization: the change in the electromagnetic wave shape around the channel and changes in the magnitudes of the measured fields for the same distance from the base of the channel but different azimuth angle.