ocr: SUN-EARTH CONNECTION When a flare occurs on the Sun, a large increase in UV/EUV/X-ray radiation follows. The radiation travels at the speed of light, and so arrives at Earth just eight minutes after leaving the flare site, well ahead of any particles or coronal material associated with the flare. The direct response of the upper atmosphere is a temporary increase in ionization (as well as temperature). Lasting from mi- nutes to hours, the phenomenon is called a sudden ionospheric disturbance (SID). It can lead to disturbances in radio communica- tions. CMES are composed of a cloud of charged p ...
