The Slow Front and Fast Transition in Close Electric and Magnetic Field and Field-Derivative Waveforms Produced by First Strokes of Natural Lightning

摘要

We examine the s ow front and fast transition in the measured close (within a few hundred meters)electric and magnetic fie d and field-derivative waveforms produced by negative and positive first return strokes in natura cloud-to-ground ightning.The characteristics of these waveforms,especia y the fine structure of the field derivative waveforms,are similar to those of distant fie ds and field derivatives measured by others.Further,preliminary modeling results,based on a two-wave version of the transmission line (TL)mode ,are in reasonable agreement with the measurements.