On the Sun [ http://www.seds.org…], S marks the spot. Solar explosions have been discovered [ http://science.nasa…] to explode preferentially from regions marked with this letter. The surface of the quiet Sun [ http://antwrp.gsfc.…] is a maze of hot gas and flowing magnetic fields [ http://vestige.lmsa…]. When two regions of high magnetic field strength approach each other, they typically pass uneventfully. If the two regions pass close enough and in just the right way, however, an X-ray [ http://imagine.gsfc…] bright S-shaped region called a sigmoid [ ftp://ftp.hq.nasa.g…] forms and quickly explodes in a Coronal Mass Ejection [ http://www-istp.gsf…] (CME). Astronomers conjecture that in the center of the sigmoid, a circuit closes that somehow drives the explosion. The above picture [ http://solar.physic…] shows the Sun [ http://antwrp.gsfc.…] in X-ray light. A pre-CME [ http://antwrp.gsfc.…] sigmoid is shown on the left inset image, while a post-CME [ http://www-solar.dc…] arc is shown in the right inset.
Explanation
On the Sun [ http://www.seds.org…], S marks the spot. Solar explosions have been discovered [ http://science.nasa…] to explode preferentially from regions marked with this letter. The surface of the quiet Sun [ http://antwrp.gsfc.…] is a maze of hot gas and flowing magnetic fields [ http://vestige.lmsa…]. When two regions of high magnetic field strength approach each other, they typically pass uneventfully. If the two regions pass close enough and in just the right way, however, an X-ray [ http://imagine.gsfc…] bright S-shaped region called a sigmoid [ ftp://ftp.hq.nasa.g…] forms and quickly explodes in a Coronal Mass Ejection [ http://www-istp.gsf…] (CME). Astronomers conjecture that in the center of the sigmoid, a circuit closes that somehow drives the explosion. The above picture [ http://solar.physic…] shows the Sun [ http://antwrp.gsfc.…] in X-ray light. A pre-CME [ http://antwrp.gsfc.…] sigmoid is shown on the left inset image, while a post-CME [ http://www-solar.dc…] arc is shown in the right inset.
