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.
... a fine world to be sleeping on. Outside the capital city its spaceport received shipments of luxuries and raw materials from halfway across the galaxy. Its landing grid reared skyward and tapped the planet's ionosphere for power with which to hoist ships to clear space and pluck down others from emptiness. There was commerce and manufacture and wealth and culture, and Walden modestly admitted that its standard of living ... — The Pirates of Ersatz • Murray Leinster
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