Our Active Ionosphere

Charged particles in Earth's upper atmosphere are formed when ultraviolet radiation from the Sun ionizes atoms and molecules in the atmosphere by knocking out electrons. In combination with Earth's intrinsic geomagnetic field, the electromagnetic interaction of this ionized plasma can form large-scale structures such as the equatorial ionization anomaly (Interface to Space: The Equatorial Fountain). The upper atmosphere, once energized by exposure to ultraviolet light during the day, can re-emit some of this energy after sunset.

Other events, such as geomagnetic storms applying forces from above and terrestrial weather applying forces from below, can drive smaller scale variations within the ionosphere. These can result in the formation of “bubbles” of lower ultraviolet emission and “X” features depicted here.

While these features have been observed before, NASA’s Global-scale Observations of the Limb and Disk (GOLD) mission has provided more complete coverage of these regions, allowing us to see more variations. This is important because variations in the ionosphere affect signals traveling between the ground and satellites, like radio communications and global positioning systems.

A 'Rayleigh' is a unit of measure suitable for low light intensities, such as the night sky and aurora.

See NASA.gov