Friday, October 12, 2012

AR 1589, Most Active for October 11th...

The above image was taken October 11th at 08:04:00 UTC by the Atmospheric Imaging Assembly (AIA), at 131 Angstroms, aboard the Solar Dynamics Observatory (SDO). This was at the time of a C4 x-ray flare near the northeast (upper-left) limb, produced by Active Region 1589 (AR 1589). Image Credit: SDO/AIA

For the end of October 10th and most of October 11th, the solar activity was low. Active Region 1589 (AR 1589), in the northeast quadrant, was responsible for the largest flare of the period; a C4 x-ray flare on the 11th at 08:04 UTC. AR 1589 is currently the most complex region, with a Beta-Gamma magnetic classification. New region AR New Region 1590 rotated onto the southeast limb and was numbered.  No Earth-directed coronal mass ejections were observed. The forecast through October 14th: The solar activity is expected to be low with a chance for isolated M-class activity.

Here at home, the geomagnetic field was quiet.  Solar wind speed, measured at the Advanced Composition Explorer (ACE) spacecraft, was slightly elevated between approximately 440 to 500 km/s while the Bz component of the interplanetary magnetic field did not vary much beyond +/- 4 nT. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels throughout the period. The forecast through October 14th: The geomagnetic field is expected to be mostly quiet on 12th and 13th. On the 14th, a coronal hole high-speed stream is expected to move into geoeffective position, causing quiet to unsettled conditions with a chance for active periods. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (, the Solar and Heliospheric Observatory (SOHO) (, the Advanced Composition Explorer (ACE) (, and the Solar Terrestrial Relations Observatory (STEREO) (


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