electrojet

An electrojet is a narrow, intense current of electric current that flows within the Earth's ionosphere, typically concentrated in specific latitudinal bands. These currents are characterized by their high conductivity and are often associated with geomagnetic disturbances caused by solar wind interactions with the Earth's magnetic field. Electrojets are most prominently observed during periods of increased solar activity, such as geomagnetic storms, when the solar wind carries charged particles toward the Earth.

The most well-known electrojet is the Equatorial Electrojet (EEJ), which flows eastward along the magnetic equator between approximately 10° and 20° magnetic latitude. This current is strongest during the day due to the ionization of the atmosphere by solar radiation, which increases electrical conductivity. The EEJ plays a significant role in the dynamics of the Earth's magnetic field, particularly in the equatorial region, and can influence radio wave propagation.

Another notable electrojet is the Polar Electrojet, which flows near the auroral zones at high latitudes (around 60°–70° magnetic latitude). Unlike the EEJ, the Polar Electrojet is more active during geomagnetic storms and is associated with the auroral oval, where charged particles from the solar wind excite atmospheric gases, producing auroras. These currents contribute to geomagnetic variations and can induce electric fields and currents in long conductors on the ground, such as power lines and pipelines.

Electrojets are studied using ground-based magnetometers, which measure variations in the Earth's magnetic field caused by these currents. Research into electrojets helps scientists understand space weather phenomena, which can affect satellite operations, radio communications, and power grids. The behavior of electrojets is influenced by factors such as solar wind dynamics, the Earth's magnetic field configuration, and atmospheric composition.