What is EUV?
Extreme ultraviolet (EUV) is radiation with wavelengths roughly between 10 and 121 nm. The Sun emits EUV from the corona and from active regions. EUV is largely absorbed by Earth's atmosphere and does not reach the ground, but it ionizes the ionosphere (creating the D, E, and F layers), which affects radio propagation and GPS.
Role in Space Weather
EUV varies with the solar cycle and with flares. During flares, increased EUV can cause sudden ionospheric disturbances and radio blackouts. Spacecraft such as SDO image the Sun in EUV to monitor active regions and eruptions for space weather forecasting.
Sources and further reading
- NASA SDO – EUV and solar imaging
- NOAA SWPC – Space weather and ionospheric effects
- ESA – Ionosphere – Ionosphere and EUV