NLN Aurora Brief – October 26, 2015

Aurora Brief Number 7 of 14
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Today on the Sun:

Solar activity continues at very low levels with decreasing activity. Today the highest level of flare activity measured was a B9.7 flare from AR 2436. AR 2436 is still the most complex and largest region on the disk, it is slightly smaller than yesterday, but is still showing slight growth in its middle spots. It is unlikely to produce significant flaring unless it becomes more complex. The was a CME reported in LASCO imagery, but it appears to have come from a backsided event so it will not have any impact on Earth.

On Earth, The expected CME arrived right on schedule, but the orientation was not conducive to generating Aurora. The N/S component of the magnetic fields, the Bz, remained North nearly the entire period. For a CME impact to generate aurora generally it has to be oriented South. As of now, there is no way of knowing the orientation of a CME until it arrives at Earth – that is the primary reason so many geomagnetic watches leave disappointed aurora hunters as they expire.

This day in 2003:

Activity on the Sun in 2003 continues to heat up. Both regions 484 and 486 produced long-duration X1.2 flares. These flares both produced fast moving partial-halo CMEs. Both will arrive at Earth over the next couple days to start an impressive period of storming. In addition to the flares, two filaments, 18-degrees and 12-degree erupted and produced CMEs. Both of the filament related CMEs were well to the west (behind) of Earth and won’t impact the magnetosphere.

Magnetogram from the sun Oct 26, 2003 showing AR484 and 486
Magnetogram from the sun Oct 26, 2003 showing AR484 and 486

On Earth, activity was quiet, but a new watch is posted indicating possible minor to isolated major aurora storming on days 2 and 3

Happy Hunting