NLN Aurora Brief – October 30, 2015

Aurora Brief Number 11 of 14
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Today on the Sun:

Flare activity increased slightly from yesterday with several C-class flares erupting mostly from active region 2443. AR 2443 was numbered in the period and now that it is in view after rotating fully onto the east limb. It was classified with a Beta magnetic structure but it is too early to tell if it is stable, growing or decaying. The other regions on the disk stayed remained stable and inactive.

A major CME event happened beyond the west limb. This was the second in as many days from roughly the same area. Both CMEs can be seen launching in LASCO C3 imagery. Notice the proton radiation “snow” on the second storm. As radiation from the explosion arrives at the camera, it appears as particles hitting the sensor. These show up as fast moving white specs. This event will not produce geomagnetic activity on Earth, so just enjoy the LASCO show.

First of Two CMEs shown in LASCO C3. October 28, 2015
First of Two CMEs shown in LASCO C3. October 28, 2015
Second of two CMEs shown in LASCO C3. October 29, 2015
Second of two CMEs shown in LASCO C3. October 29, 2015

As if that wasn’t enough, there were also two disappearing filaments in the last 24 hours. Both of these happened late enough that analysis on whether they produced CMEs won’t be complete until tomorrow. The CME launched by the filament mentioned in yesterday’s brief was determined to not have an Earth directed component. The CME from yesterday’s filament eruption is visible coming off the center right of the sun in the first animated GIF above, just after the large CME.

Finally, the big coronal hole continues to rotate towards the Earth strike zone. This feature represents the most likely source of aurora over the next week. It should start to influence the solar wind speed around 11/2 or 11/3. As mentioned before, this CH has a history of generating geomagnetic storming on Earth. Here is the twitter post NLN posted on the coronal hole’s previous rotation on Oct 6

This Day on 2003:

The X10 flare that was ongoing at the end of 10/29/2003 continued on through the beginning of 10/30. It produced another extremely fast (1900 KM/s) Earth-directed CME. The CME arrived at Earth just 19 hours after the flare. When it arrived the shock altered the Earth’s magnetopause so greatly that ACE satellites that collect readings were outside of the magnetopause for much of the storm. Bz reading most of the day stayed in the -15 to -30 range – which produced very strong geomagnetic activity. Active Region 486, which produced this flare, grew to 2500 millionths, by far the largest for this solar cycle. From this point forward the active region would begin to decay.

On Earth aurora hunters experienced a severe geomagnetic storm most of the day. KP ranged from 7-9 expect for a brief period between when the X17 flare impacts started to wane and the X10 flare CME shock arrived. Even in those relatively “calm” periods, KP remained at minor storm levels of KP 5-6.

Happy Hunting!