Also found in: Thesaurus, Encyclopedia, Wikipedia.
A region of the earth's atmosphere where ionization caused by incoming solar radiation affects the transmission of radio waves. It extends from a height of 70 kilometers (43 miles) to 400 kilometers (250 miles) above the surface.
i·on′o·spher′ic (-sfîr′ĭk, -sfĕr′-) adj.
the region of the earth's atmosphere between the stratosphere and the exosphere, consisting of several ionized layers and extending from about 50 to 250 mi. (80 to 400 km) above the surface of the earth.
i•on`o•spher′ic (-ˈsfɛr ɪk) adj.
A region of the Earth's atmosphere in which atoms are often ionized (electrically charged) by radiation from the sun. The ionosphere lies mostly in the lower thermosphere, from about 43 to 250 miles (69 to 402.5 kilometers) above the Earth. Radio waves, which normally travel in a straight line, can be transmitted long distances over the curved surface of the Earth because they bounce off certain layers of the ionosphere and return to Earth instead of continuing into space.
That part of the atmosphere, extending from about 70 to 500 kilometers, in which ions and free electrons exist in sufficient quantities to reflect electromagnetic waves.
the outermost part of the earth’s permanent atmosphere, beyond the stratosphere, composed of heavily ionized molecules. It extends from about 50 to 250 miles above the surface of the earth. Cf. exosphere.See also: Atmosphere
1. The upper layer of the atmosphere that lies above the stratosphere and is about 217 mi (350km) thick.
2. The area of the Earth’s atmosphere in which ionization caused by solar radiation affects the transmission of radio waves.
Switch to new thesaurus
|Noun||1.||ionosphere - the outer region of the Earth's atmosphere; contains a high concentration of free electrons|
atmosphere, air - the mass of air surrounding the Earth; "there was great heat as the comet entered the atmosphere"; "it was exposed to the air"
D region, D-layer - the lowest region of the ionosphere (35 to 50 miles up) that reflects low-frequency radio waves
Appleton layer, F layer, F region - the highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission
E layer, E region, Heaviside layer, Kennelly-Heaviside layer - a region of the ionosphere (from 50 to 90 miles up) that reflects radio waves of medium length