ionosphere

ionosphere
The region of the atmosphere, extending from approximately 30 to 250 miles (50 to 400 km), in which there is appreciable ionization. The ionized layers in the atmosphere reflect radio waves, making long-wave communications possible over the earth’s surface. The ionosphere is classically subdivided into layers (i.e., D, E, F, and G layers), and the portions of the ionosphere where these layers tend to form are called the D, E, F, and G regions, respectively. Each layer, except the D layer, is supposedly characterized by a more or less regular maximum of electron density. The D layer exists only in the daytime. It is not strictly a layer at all, since it does not exhibit a peak of electron or ion density. It starts at about 30 miles (50 km) and merges with the bottom of the E layer (at a height of 60 miles, or 100 km). The lowest clearly defined layer is the E layer, which occurs at heights between 60 and 90 miles (about 100 to 150 km). The F1 layer and the F2 layer occur in the general region between 90 and 210 miles (150 and 350 km); the F2 layer is always present and has the higher electron density. The G layer exists above the F layer.

Aviation dictionary. 2014.

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  • IONOSPHÈRE — L’atmosphère est ionisée sur toute la surface du globe à partir d’une altitude d’environ 60 km, au dessous de laquelle l’ionisation est négligeable; cette région de l’atmosphère est appelée ionosphère. Vers les altitudes supérieures, l’ionisation …   Encyclopédie Universelle

  • Ionosphere — Ionosphère L’ionosphère est une région de l atmosphère terrestre située entre la mésosphère et la magnétosphère, c est à dire entre 60 et 800 km d altitude. Elle est constituée de gaz fortement ionisé (=plasma) à très faible pression (entre 2×10… …   Wikipédia en Français

  • 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… …   The Collaborative International Dictionary of English

  • ionosphere — 1926, from ION (Cf. ion) + SPHERE (Cf. sphere). Coined by Scottish radar pioneer Robert A. Watson Watt (1892 1973). So called because it contains many ions …   Etymology dictionary

  • ionosphere — ► NOUN ▪ the layer of the atmosphere above the mesosphere, which contains a high concentration of ions and electrons and is able to reflect radio waves. DERIVATIVES ionospheric adjective …   English terms dictionary

  • ionosphere — [ī än′ə sfir΄] n. [< ION + O + SPHERE] the outer part of the earth s atmosphere, beginning at an altitude of c. 55 km ( c. 34 mi) and extending to the highest parts of the atmosphere: it contains several regions that consist of a series of… …   English World dictionary

  • Ionosphere — The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner …   Wikipedia

  • Ionosphère — L ionosphère est l’atmosphère supérieure d’une planète, en référence à son état de conductibilité électrique qui est caractérisé par une ionisation partielle des gaz. L’ionosphère terrestre comprend trois régions neutres, à savoir la mésosphère,… …   Wikipédia en Français

  • ionosphere — ionospheric /uy on euh sfer ik/, adj. /uy on euh sfear /, n. 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… …   Universalium

  • ionosphere — jonosfera statusas T sritis fizika atitikmenys: angl. ionosphere vok. Ionosphäre, f rus. ионосфера, f pranc. ionosphère, f …   Fizikos terminų žodynas

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