E region of the atmosphere

Also found in: Dictionary, Thesaurus.

Heaviside layer

Heaviside layerclick for a larger image
A layer of ionized particles that surrounds the earth. The layer, also called the E layer, has ionization of around 106 free electrons. The layer is found at a height of around 60 to 90 miles (100-150 km), but its height varies according to the seasons and during the day and at night. The Heaviside layer reflects relatively long, low-frequency radio waves ranging from 100 kHz to 20 MHz. Also called the Kennelly-Heaviside layer and the E region of the atmosphere.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved