Partial CME impact causes geomagnetic storm

Added by Erik West on September 26, 2011

Flares from Sunspot 1302 resulted in Coronal Mass Ejections (CMEs) partially directed at Earth, resulting a geomagnetic storm rated by the NOAA as Strong to Extreme on Monday.

The NOAA reported that solar wind speeds had increased from 300km/sec to over 600km/sec at 12:15 UTC, indicating the arrival of a CME released two days ago by Sunspot 1302, which was partially directed towards Earth at the time of the flare activity that began on September 22.

This is a developing story – updates may be posted here as new information becomes available.

The Goddard Space Weather Lab reported a strong compression of the Earth’s magnetosphere. As a result, some satellites could be directly exposed to solar wind and the effects of magnetic fields.

Amateur radio operators are reporting that they are detecting radio propagation at 50 MHz and 144 MHz, and expect radio contact in North America within several hours. Radio propagation is a measure of radio frequencies caused by events like CMEs.

Geomagnetic storms primarily result in Auroral activity, can effect orbiting satellites, and may cause temporary radio blackouts on Earth. Auroras are natural light displays caused by the collision of charged particles with atoms at high altitudes and are directed by the Earth’s magnetic field. Auroras typically occur between 10-20 degrees from the magnetic North pole within a 3-6 degree band, regardless of longitude.

A monitoring station in Norway reports detection of electrical ground currents, or stray voltage, as a result of the CMEs. An electrical ground current is stray voltage emanating from the ground, which is normally at neutral voltage – electrical ground currents are not dangerous to living things.

Update (Sept 27 2011 – 00:16 UTC): There have been  8 M-class and 13 C-class flares during the past 48h. The probability of flares from sunspot 1302 during the next 48h are: X-class: 31%; M-class: 41%; C-class: 54%

• X-class flares are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms.
• M-class flares can cause brief radio blackouts that affect Earth’s polar regions. Minor radiation storms sometimes follow an M-class flare.
• C-class flares are small with few noticeable consequences here on Earth.

The last observed flare for September 26 was a class M at 16:51 UTC originating from sunspot 1302.

Do you have any photos or reports of Aurora in your area? Leave a comment.