Abstract

The effects of strong vertical atmospheric electric fields and electrically charged raindrops on the primary rainbow are considered. A vertical electric field alters the bow by stretching the raindrops vertically. The effects may be visible only for the extremely large electric fields (E > 10⁵ V m⁻¹) sometimes encountered in thunderstorms. The electric field raises and brightens the top of the primary bow but reduces the relative intensity and spacing between the supernumeraries. Electrical charges do not have any visible effect on the rainbow because they significantly increase the ellipticity of only the largest and most highly charged drops, which do not contribute to the bow’s top.

© 1988 Optical Society of America

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