Tuesday, October 02, 2012

AR 1575's C9 Flare on Sept 30th...

The above image was taken September 30th at 23:39:00 UTC by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). This was during the time of a C9 solar x-ray event, produced by Active Region 1575 (AR 1575), beyond the western (right) limb. The displayed image combined the AIA observations at 94, 131, and 171 Angstroms. Image Credit: SDO/AIA

For the end of September 30th and most of October 1st, the solar activity was low. Active Region 1575 (AR 1575), which is now around the west limb, produced several C-class x-ray events, the greatest being a C9 on the 30th at 23:39 UTC. No Earth-directed coronal mass ejections (CMEs) were observed. The forecast through October 4th: The solar activity is expected to be low for the 2nd. Activity is expected to be very low to low on the 3rd and 4th, as the complex or regions near the western extent of the visible solar disk continue beyond the limb.

Above Earth, the geomagnetic field began the period at active levels, as weak CME effects from the previous 24 hours continued in progress. The beginning of the 1st saw an increase to severe storm levels, after a second CME arrived at the Advanced Composition Explorer (ACE) on the 30th around 22:21 UTC with a subsequent Sudden Impulse (SI) to Earths magnetic field (35nT measured at Boulder) at 23:07 UTC. A single major storm period followed, before conditions decreased to active and then again to quiet. The forecast through October 4th: The geomagnetic field is expected to be quiet to unsettled on the 2nd as CME effects wane. The 3rd and 4th should see mostly quiet conditions. 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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