Intensity Variations in the Channel of the Return Lightning Stroke

Abstract

PHOTOGRAPHY of lightning strokes with the Boys camera has shown that each separate stroke is of a dual nature, consisting of a leader and a return portion. It has been shown that the return stroke travels from ground to cloud, passing outwards along the branches when it reaches branching points of the leader. The charge on the leader branches passes in this manner to ground. It has also been shown that there is a marked diminution in the intensity of the light emitted from the main channel after the return stroke has passed a prominent branch.