ionosphere n. The outer region of the earth's atmosphere, beyond which is the exosphere; it contains a high concentration of free electrons and ions, and extends from about 50 miles to about 250 miles above the earth's surface, but the height shows daily and seasonal variation, and the composition of the particles in the ionosphere is also affected by events such as solar flares.
... landing grid near the biggest city—that half-mile-high, cagelike wall of intricately braced steel girders. It tapped the planet's ionosphere for all the power that this world's inhabitants could use, and applied the same power to lift up and let down the ships of space by which communication with the rest of humanity was maintained. From this distance, though, even with ... — The Hate Disease • William Fitzgerald Jenkins Read full book for free!