EIT images of a solar flare
Active region 10486 on the Sun, which was already under close scrutiny by several instruments on board SOHO and other satellites, as well as numerous ground observatories, started up a spectacular two-part show in the morning on Tuesday 28 October 2003.
An X 17.2 flare, the second largest flare observed by SOHO, set off a strong high energy proton event and a fast-moving Coronal Mass Ejection (CME), hitting the Earth early on Wednesday 29 October. The encore came on Wednesday afternoon, when an X 10.0 flare from the same active region set off another round of particles and another fast-moving CME.
These images from the Extreme ultraviolet Imaging Telescope (EIT) on board SOHO show the Sun on 28 October 2003, and were taken through a filter centred at 195 Ångström. The image on the left is from 11:12 UT and shows the first of the two flares. The image on the right was taken between the two flares, at 23:45 UT, when the instrument was showered in the ensuing storm of energetic particles from the Sun.
The two images can also be downloaded individually from the right-hand menu under "related images".