Impact of Solar Flares on Amateur Radio

Impact of Solar Flares on Amateur Radio

Solar flare is a localized intense eruption of electromagnetic radiation from the Sun’s atmosphere. They may be accompanied by coronal mass ejections. Coronal mass ejections can generate radio bursts that reaches Earth in minutes and can last up to tens of hours. Geomagnetic storms can occur in response to these phenomena, causing even a 45 dB increase in attenuation of radio signals arriving via the ionosphere.

Coronal mass ejection is an eruption magnetic field and plasma mass from the Sun’s corona into the heliosphere, which is the outermost atmospheric layer of the Sun. If they reach interplanetary space, they can reach the Earth’s magnetosphere and cause geomagnetic storms, aurora and rarely damage electrical power grids.

Solar flares increase extreme ultraviolet (EUV) and X-ray energy which causes rapid increase in ionization of the D-layer of the ionosphere. As D-layer of the ionosphere is present on the daytime side of the globe, this can cause complete fading out of dayside HF communications. The problem can last from a few minutes to an hour or sometimes more. As the solar EUV and X-ray energy takes only about 8 minutes to reach the Earth, advance warning of this effect is not possible.