August 18th, Lots A-Poppin'!

The above X-ray image of the sun was taken August 19th at 04:12 UTC by the Solar X-ray Imager (SXI) aboard the GOES-15 satellite. Image Credit: NOAA

On August 18th at 01:02 UTC, Active Region 1548 (AR 1548) produced a M5-class solar flare, accompanied by a Tenflare — a radio burst of 10cm or greater. Later, at 03:23 UTC, that same region produced an M1-class flare, also accompanied by a Tenflare. Finally, AR 1558 produced an M2-class flare at 16:07 UTC. Several coronal mass ejections (CMEs) were observed during this turmoil, but none appear to have any possible impact on Earth's geomagnetic field.

CMEs have been just a-poppin' of late. On August 17th, the instruments aboard the Solar Dynamics Observatory (SDO) observed a filament eruption near AR 1543 around 16:00 UTC. And a CME was subsequently observed by the LASCO C2 coronagraph aboard the Solar Heliospheric Observatory (SOHO), at 18:36 UTC. And LASCO C3 instrument observed another CME at 19:18 UTC. AR 1543 had a second filament eruption and CME between the 17th at 22:00 UTC and the 18th at 00:34 UTC. Shortly thereafter, it was visible by the COR2 instrument aboard the STEREO-B satellite at 01:10 UTC. And then observed by SOHO's LASCO C3 coronagraph at 04:54 UTC. These observations have confirmed that this CME was definitely directed well north of the ecliptic. The solar activity forecast for the 19th through 21st is expected to be low, but with moderate activity likely.

Here at Earth, the geomagnetic field activity for August 18th has ranged from quiet to active. The ACE spacecraft rated the solar wind speed at about 350-420 km/s.ACE noted the solar wind density increased sharply after 19:00 UTC on the 18th. The geomagnetic field reached active levels between 18:00 UTC and 21:00 UTC. This increase coincided with a change to the sector and the arrival of the co-rotating active region. For August 19th through the 21st, the geomagnetic field is expected to range from quiet to unsettled, as that co-rotating interaction region and the coronal hole high speed stream continues to have an affect. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center, URL: www.swpc.noaa.gov .

To learn more about the Sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO), sdo.gsfc.nasa.gov and the Solar and Heliospheric Observatory (SOHO), sohowww.nascom.nasa.gov .

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