- —magnetospheric /mag nee'teuh sfer"ik/, adj./mag nee"teuh sfear'/, n. Astron.1. the outer region of the earth's ionosphere, where the earth's magnetic field controls the motion of charged particles, as in the Van Allen belts. Cf. magnetopause.2. such a region of another planet: Jupiter's magnetosphere.[1955-60; MAGNETO- + -SPHERE]
* * *Region around a planet (such as Earth) or a natural satellite that possesses a magnetic field (see geomagnetic field) where magnetic phenomena and the high atmospheric conductivity caused by ionization strongly influence the behaviour of charged particles (see electric charge).A planet or moon's magnetic field, like its gravitational field, becomes weaker with distance from the body. The solar wind sweeps a body's magnetosphere out away from the Sun in a "tail" trailing well beyond it.
* * *region in the atmosphere where magnetic phenomena and the high atmospheric conductivity caused by ionization are important in determining the behaviour of charged particles.The Earth, in contrast to Mars and Venus, has a significant surface magnetic field (approximately 0.5 gauss), which, like its gravitational field, becomes weaker as the distance from the centre of the Earth increases. In the direction of the Sun, at approximately 10 Earth radii (almost 65,000 km, or 40,000 miles), the magnetic field is so weak that the pressure associated with particles escaping from the Earth's gravity is comparable to the opposing pressure associated with the solar wind—the flux mainly of protons and electrons escaping from the Sun's gravitational field. This equilibrium region, with a characteristic thickness of 100 km (60 miles), is called the magnetopause and marks the outer boundary of the magnetosphere. The lower boundary of the magnetosphere is several hundred kilometres above the Earth's surface.On the night side, or the side away from the Sun, the forces associated with the magnetic field and the solar wind are parallel, and thus the magnetosphere extends a considerable distance, possibly even several astronomical units (one astronomical unit is the average distance between the Earth and the Sun, about 1.5 × 108 km).In the direction perpendicular to the solar wind, the random motion of the solar-wind particles exerts a small pressure on the magnetic field, constricting the magnetosphere slightly. The net result is that the shape of the magnetosphere in gross terms is similar to that of a comet, with the Earth located near the nucleus, or head, of the “comet” and the magnetospheric “tail” trailing out well beyond the Earth, away from the Sun.Between 10 and 13 Earth radii toward the Sun, there exists the magnetosheath, a region of magnetic turbulence in which both the magnitude and direction of Earth's magnetic field vary erratically. This disturbed region is thought to be caused by the production of magnetohydrodynamic shock waves, which in turn are caused by high-velocity solar-wind particles. Ahead of this bow shock boundary, toward the Sun, is the undisturbed solar wind.
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Magnetosphere — Magnétosphère La magnétosphère est la région entourant un objet céleste dans laquelle les phénomènes physiques sont dominés ou organisés par son champ magnétique. Toute planète dotée d un champ magnétique (la Terre, Jupiter, Saturne, Uranus et… … Wikipédia en Français
magnétosphère — [ maɲetɔsfɛr ] n. f. • av. 1966; de magnéto et sphère, d apr. atmosphère ♦ Géophys. Région de l espace entourant la Terre dans laquelle est confiné le champ magnétique terrestre. ● magnétosphère nom féminin Zone dans laquelle le champ magnétique… … Encyclopédie Universelle
magnetosphere — mag*net o*sphere, n. the magnetic field of a planet; the volume around the planet in which charged particles are subject more to the planet s magnetic field than to the solar magnetic field. [WordNet 1.6] … The Collaborative International Dictionary of English
magnetosphere — (n.) 1959, from MAGNETO (Cf. magneto ) + SPHERE (Cf. sphere). So called because in it the magnetic field of the earth plays a dominant role in the motion of particles … Etymology dictionary
magnetosphere — [mag nēt′ō sfir΄, magnēt′əsfir΄; magnet′ō sfir΄, magnet′ə sfir΄] n. [ MAGNETO + SPHERE] that region surrounding a planet in which the planet s magnetic field is stronger than the interplanetary field: the solar wind gives it a cometlike shape… … English World dictionary
Magnetosphere — A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets… … Wikipedia
Magnétosphère — La magnétosphère est la région entourant un objet céleste dans laquelle les phénomènes physiques sont dominés ou organisés par son champ magnétique. Toute planète dotée d un champ magnétique (la Terre, Jupiter, Saturne, Uranus et Neptune) possède … Wikipédia en Français
magnetosphere — magnetosfera statusas T sritis ekologija ir aplinkotyra apibrėžtis Erdvė, kurioje kosminio kūno, pvz., Jupiterio, Žemės, magnetinis laukas sąveikauja su kosminių elektringųjų dalelių srautais. atitikmenys: angl. magnetosphere vok. Magnetosphäre,… … Ekologijos terminų aiškinamasis žodynas
magnetosphere — noun Date: 1959 a region of space surrounding a celestial object (as a planet or star) that is dominated by the object s magnetic field so that charged particles are trapped in it • magnetospheric adjective … New Collegiate Dictionary
magnetosphere — noun The comet shaped region around Earth or another planet in which charged particles are trapped or deflected. Shaped by the solar wind and the planets magnetic field … Wiktionary