Monday, February 18, 2013
The Sun's AR11675 M1.9 is putting us on notice HD
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New sunspot AR1675 has unleashed the most intense flare of the year so far, an M1.9-class explosion at 1550 UT on Feb. 17th. First-look coronagraph images from SOHO and the twin STEREO probes suggest that this explosion did not produce a coronal mass ejection (CME). Geomagnetic storms are therefore unlikely. Earth's upper atmosphere, however, probably did experience a minor wave of ionization caused by the UV flash.