Encyclopedia of Solid Earth Geophysics

Living Edition
| Editors: Harsh K. Gupta

Equatorial Electrojet

  • Archana BhattacharyyaEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-030-10475-7_155-1


The equatorial electrojet (EEJ) is a narrow band of intense electric current that flows along the dip equator in the day side ionospheric E region with peak current density at an altitude of around 105 km.


Electrical conductivity of the partially but significantly ionized upper atmosphere of Earth is anisotropic due to presence of Earth’s magnetic field. In the ionospheric E region, movement of electrons in response to an electric field is influenced by the geomagnetic field, whereas for the heavier ions, collisions with neutral particles have much greater influence. This difference in the behavior of electrons and ions gives rise to a large Hall conductivity in the E region. Atmospheric tides, driven mainly by solar heating and to a lesser extent by the gravitational pull of moon, cause the neutral atmosphere to undergo global-scale oscillations, with harmonic periods of a day. These oscillations, through ion-neutral collisions, set the electrically conducting...

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Authors and Affiliations

  1. 1.Indian Institute of GeomagnetismNavi MumbaiIndia