Major solar flares erupting behind the northeast limb

A major solar flare was detected behind Sun's northeast limb on September 1, 2014. STEREO Behind spacecraft, watching farside of the Sun, captured what is most likely an X-class solar flare starting at 11:05 UTC.

This major solar flare was associated with a Type II Radio Emission with velocity of 2 079 km/s, a significant radio bursts and solar proton storm.

A halo or partial-halo Coronal Mass Ejection (CME) produced by this eruption is not Earth directed. However, this region will soon appear on the Earth side of the Sun and if it keeps its present state of activity we can expect CME impacts very soon.

More strong solar flares were observed off the east limb after the 11:05 UTC event but since no spacecraft watching the farside of the Sun can precisely classify the actual strength of farsided flares it is only assumed that they are of the X or near X class strength. The assumption is based on the appearance at UV wavelengths and solar radiation storms.

Additionally, in latest Forecast discussion issued at 12:30 UTC today SWPC noted that a nearly 38 degree long filament appeared to be beginning to lift off from the corona. However, at the time it had not erupted nor lifted off.

Space Weather Message Code: ALTTP2
Serial Number: 956
Issue Time: 2014 Sep 01 1139 UTC

ALERT: Type II Radio Emission
Begin Time: 2014 Sep 01 1113 UTC
Estimated Velocity: 2079 km/s
Description: Type II emissions occur in association with eruptions on the sun and typically indicate a coronal mass ejection is associated with a flare event.

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Video courtesy of SolarHam using images from STEREO Behind EUVI 195

Energetic particle summary and forecast

24 hr summary

The greater than 2 MeV electron flux was at normal to high levels during last 24 hours, reaching a peak flux value of 3504 pfu at 15:15 UTC on September 1.  The greater than 10 MeV proton flux was slightly elevated due to the large, non-Earth sided event, but remained below alert threshold levels.

Forecast

The greater than 2 MeV electron flux is expected to be at normal to high levels for the next three days (September 2 – 4).  The greater than 10 MeV proton flux is expected to remain slightly enhanced, but below alert threshold levels (S1-Minor) for the next three days. (SWPC at 12:30 UTC / September 2, 2014)

Low energy electrons & protons

High energy protons

Space Weather Message Code: ALTEF3
Serial Number: 2117
Issue Time: 2014 Sep 02 0946 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2116
Begin Time: 2014 Aug 30 1335 UTC
Yesterday Maximum 2MeV Flux: 3505 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

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A similar event to that from 11:05 UTC on September 1, although much less intensive, was first registered on SOHO/Lasco C2 imagery around 16:00 UTC:

 

Another major eruption was observed just after 22:00 UTC yesterday and was associated with a Type IV Radio Emission:

Space Weather Message Code: ALTTP4
Serial Number: 474
Issue Time: 2014 Sep 01 2340 UTC

ALERT: Type IV Radio Emission
Begin Time: 2014 Sep 01 2250 UTC
Description: Type IV emissions occur in association with major eruptions on the sun and are typically associated with strong coronal mass ejections and solar radiation storms.

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Space Weather Message Code: ALTTP2
Serial Number: 957
Issue Time: 2014 Sep 01 2339 UTC

ALERT: Type II Radio Emission
Begin Time: 2014 Sep 01 2211 UTC
Estimated Velocity: 1904 km/s
Description: Type II emissions occur in association with eruptions on the sun and typically indicate a coronal mass ejection is associated with a flare event.

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Image copyright Zoltan Kenwell (InFocusImagery.com)

Exciting solar related events are ahead of us, it is a good time to prepare and wait for Earth directed CMEs. If they do arrive and you happen to capture their visual effects on Earth it'd be great if you could share them with us.

Featured image: Major solar flare observed by SOHO/Lasco C3 coronagraph on September 1, 2014.