Present understanding of the lightning return stroke

Abstract

In this chapter, a general picture of downward negative lightning discharges that take place between cloud and ground are described. Then, first and subsequent return strokes, which are the optically brightest processes and produce the most intense wideband electromagnetic signatures in the overall cloud-to-ground lightning discharge, referred to as the lightning flash, are presented. The first return stroke follows the path of initial downward-progressing stepped leader emerging from the cloud, and subsequent return strokes are usually initiated by dart leaders propagating downward along channels traversed by the preceding stroke(s). Representative models of lightning return strokes are also described. © Springer Science+Business Media B.V. 2009.