Electrojet

Electrojet

An electroject is an electric current which travels around the E region of the Earth's ionosphere. There are three electrojets: above the magnetic equator (the equatorial electrojet), and near the Northern and Southern Polar Circles (the Auroral Electrojets). Electrojets are Hall currents carried primarily by electrons at altitudes from 100 to 150 km. In this region the electron gyro frequency (Larmor frequency) is much greater than the electron-neutral collision frequency. In contrast, the principle E region ions (O2+ and NO+) have gyrofrequencies much lower than the ion-neutral collision frequency.

Kristian Birkeland was the first to suggest that polar electric currents (or auroral electrojets) are connected to a system of filaments (now called "Birkeland currents") that flow along geomagnetic field lines into and away from the polar region.

Equatorial Electrojet

The worldwide solar-driven wind results in the so-called Sq (solar quiet) current system in the E region of the Earth's ionosphere (100-130 km altitude). Resulting from this current is an electrostatic field directed E-W (dawn-dusk) in the equatorial day side of the ionosphere. At the magnetic dip equator, where the geomagnetic field is horizontal, this electric field results in an enhanced eastward current flow within ± 3 degrees of the magnetic equator, known as the equatorial electrojet.


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  • électrojet — ● électrojet nom masculin Courant électrique atmosphérique. ● électrojet (expressions) nom masculin Électrojet équatorial, courant ionosphérique responsable de variations du champ magnétique terrestre à basse altitude …   Encyclopédie Universelle

  • electrojet — [ē lek′trō jet΄, ilek′trō jet΄; ē lek′trə jet΄, i lek′trəjet΄] n. a narrow, high velocity stream of electric energy that girdles the earth in the ionosphere above the magnetic equator and near the auroral displays …   English World dictionary

  • Électrojet équatorial — ● Électrojet équatorial courant ionosphérique responsable de variations du champ magnétique terrestre à basse altitude …   Encyclopédie Universelle

  • electrojet etching — elektrolitinis čiurkšlinis ėsdinimas statusas T sritis radioelektronika atitikmenys: angl. electrojet etching vok. elektrolythisches Strömungsätzen, n; elektrolythisches Ätzen durch Strömung, n rus. электролитическое струйное травление, n pranc.… …   Radioelektronikos terminų žodynas

  • electrojet — noun Date: 1955 a concentration of atmospheric electric current found in the regions of strong auroral displays and along the magnetic equator …   New Collegiate Dictionary

  • electrojet — /i lek treuh jet /, n. Geophysics. a current of ions existing in the upper atmosphere, moving with respect to the surface of the earth, and causing various auroral phenomena. [1950 55; ELECTRO + JET1] * * *       streaming movement of charged… …   Universalium

  • electrojet — noun an intense electric current occurring in the lower ionosphere in the region of strong auroral displays …   English new terms dictionary

  • electrojet — e•lec•tro•jet [[t]ɪˈlɛk trəˌdʒɛt[/t]] n. phs a current of ions in the upper atmosphere that moves with respect to the surface of the earth and causes various auroral phenomena • Etymology: 1950–55 …   From formal English to slang

  • electrojet —  ̷ ̷ˈ ̷ ̷ ̷ ̷+ˌ noun Etymology: electr + jet : an overhead concentration of electric current that is restricted laterally so that in its effects it resembles a line current, that is found in the regions of strong auroral displays and along the… …   Useful english dictionary

  • Equatorial electrojet — thumb|400px|A snap shot of the Earth’s magnetic field at 400 Km altitude due to the ionsopheric current systems. The equatorial intensification of the magnetic field is due to Equatorial Electrojet (EEJ). EEJ peaks over Indian ocean region at… …   Wikipedia

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