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Lightning can cause ionospheric perturbations in the D-region in one of two ways. The first is through VLF (very low frequency) radio waves launched into the magnetosphere. These so-called "whistler" mode waves can interact with radiation belt particles and cause them to precipitate onto the ionosphere, adding ionization to the D-region.
This is called a short wave fadeout (SWF). These fadeouts last for a few minutes to a few hours and are most severe in the equatorial regions where the Sun is most directly overhead. Although High Frequency signals suffer a fadeout because of the enhanced D-layer, the Sudden Ionospheric Disturbance enhances long wave radio
Ionospheric storms are storms which contain varying densities [1] of energised electrons in the ionosphere as produced from the Sun. Ionospheric storms are caused by geomagnetic storms. [2] They are categorised into positive and negative storms, where positive storms have a high density of electrons and negative storms contain a lower density ...
The majority of the energy is deposited in the extreme lower region (D-region) of the ionosphere (around 50–80 km in altitude). This area is particularly important to ionospheric radio communications because this is the area where most of the absorption of radio signal energy occurs. The enhanced ionization produced by incoming energetic ...
When broadband very low frequency (VLF) waves propagate the radiation belts, the electrons exit the radiation belt and "precipitate" (or travel) into the ionosphere (a region of Earth's atmosphere) where the electrons will collide with ions. [2] Electron precipitation is regularly linked to ozone depletion. It is often caused by lightning strikes.
This region begins at a height of 60 km, extends up to 3 or 4 Earth radii, and includes the ionosphere. This region rotates with the Earth. [28] There are also two concentric tire-shaped regions, called the Van Allen radiation belts, with high-energy ions (energies from 0.1 to 10 MeV). The inner belt is 1–2 Earth radii out while the outer ...
A telluric current (from Latin tellūs ' earth '), or Earth current, [1] is an electric current that flows underground or through the sea, resulting from natural and human-induced causes. These currents have extremely low frequency and traverse large areas near or at Earth 's surface.
A Birkeland current (also known as field-aligned current, FAC) is a set of electrical currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere. In the Earth's magnetosphere, the currents are driven by the solar wind and interplanetary magnetic field (IMF) and by bulk motions ...