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TRACE: A Coronal Loop with a
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| Title |
TRACE: A Coronal Loop with a Co-temporal Yohkoh Soft X-ray Image Overlaid. |
| Completed |
1999-07-14 |
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Solar Magnetic Bananas
| Title |
Solar Magnetic Bananas |
| Explanation |
Is that our Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]? The unusual banana [ http://www.dole5aday.com/bobby/shocked_audio/radio_swa_letsgo.html ]-shaped loops shown above [ http://science.msfc.nasa.gov/newhome/headlines/ast22jun98_1.htm ] are actually part of a computer-generated snap-shot of our Sun's magnetic field [ http://vestige.lmsal.com/TRACE/Public/magnetic.htm ]. This animated frame [ http://science.msfc.nasa.gov/ssl/pad/solar/3dfields.htm ] was constructed using data from the ground-based U.S. Solar Vector Magnetograph [ http://wwwssl.msfc.nasa.gov/ssl/pad/solar/maggraph.htm ] and the space-based Japanese X-Ray Telescope Yohkoh [ http://solar.physics.montana.edu/YPOP/ ]. Surfaces of constant magnetic field [ http://www-spof.gsfc.nasa.gov/Education/Imagnet.html ] strength loop through the Sun's corona [ http://antwrp.gsfc.nasa.gov/apod/ap951024.html ], break through the Sun's surface, and connect regions of magnetic activity such as sunspots [ http://antwrp.gsfc.nasa.gov/apod/ap980322.html ]. Recently, contact has been interrupted [ http://sohowww.nascom.nasa.gov/pr26june.html ] with the Sun-watching SOHO [ http://sohowww.nascom.nasa.gov/ ] satellite. Although SOHO had completed its two year mission, attempts are still being made to re-establish communication. |
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Sigmoids Predict Solar Erupt
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| Title |
Sigmoids Predict Solar Eruptions |
| Explanation |
On the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ], S marks the spot. Solar explosions have been discovered [ http://science.nasa.gov/newhome/headlines/ast09mar99_1.htm ] to explode preferentially from regions marked with this letter. The surface of the quiet Sun [ http://antwrp.gsfc.nasa.gov/apod/ap970108.html ] is a maze of hot gas and flowing magnetic fields [ http://vestige.lmsal.com/TRACE/Public/magnetic.htm ]. 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.nasa.gov/docs/science/know_l1/emspectrum.html ] bright S-shaped region called a sigmoid [ ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1999/99-035.txt ] forms and quickly explodes in a Coronal Mass Ejection [ http://www-istp.gsfc.nasa.gov/istp/outreach/cmeposter/hurricane.html ] (CME). Astronomers conjecture that in the center of the sigmoid, a circuit closes that somehow drives the explosion. The above picture [ http://solar.physics.montana.edu/canfield/sigmoids.shtml ] shows the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap980830.html ] in X-ray light. A pre-CME [ http://antwrp.gsfc.nasa.gov/apod/ap961108.html ] sigmoid is shown on the left inset image, while a post-CME [ http://www-solar.dcs.st-and.ac.uk/~alan/sun_course/Introduction/Coronal_mass_ejection.html ] arc is shown in the right inset. |
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