Flares Without Sunspots

[Archmonoth]

19 hours ago, Drax Spacex said:

I'd imagine you could get a large number of hysteresis-induced C-flares tagged in the data when the background flux is vacillating about the minimim C level without an additional signal-to-noise threshold to distinguish between a flare and just fluctuating flux.

 

I think the hysteresis of the spots on the far side might help in this distinction. Is there a way to map or track spots without watching the far side?

[Drax Spacex]

7 hours ago, Archmonoth said:

Is there a way to map or track spots without watching the far side?

"Regions Due To Return" provides a list of regions rotating back into view within the next few days:  https://www.spaceweatherlive.com/en/reports/sunspot-report.html

Magnetogram synoptic charts depict a full 360° of longitude data which can be used to track regions across the far side:  https://nso.edu/data/nisp-data/synoptic-maps/

Edited August 17, 2021 by Drax Spacex
synoptic charts

[Newbie]

STEREO Ahead EUVI 195 21-08-16 23:35:00

Compare the activity of plage area (2853) on the West limb, to the small bright patch just left of it AR2857. The plage is greater. Also of interest is the two bright areas emerging over the East Limb. At the moment the magnetic canopy is nowhere near that of the plage area, hopefully that will change as it rotates further. This gives an indication of the hysteresis of the spots from the view of STEREO A as you view it over time. The spots due to return are listed, sometimes areas of plage, as well. Not all spots make the list, being deemed to have already decayed beyond plage, before they return to Earth view. There may be movies of STEREO A images around like there are with 72 hour LASCO images. 

[Drax Spacex]

The main feature I see here the Donny Darko rabbit.  Pareidolia and solar images?  Perhaps a topic for Other 🐰

[Newbie]

Donny Darko rabbit! Hahaha me too! Is there something seriously wrong with us?

Yes, it's a rather boring sun.

Edited August 17, 2021 by Newbie

[Drax Spacex]

Nahh - If medical doctors can publish a paper in a professional journal about seeing Baby Yoda in Sacral MRI and CT Scans... I think we're good!

Incidentally, when I used the word hysteresis, I was attempting to borrow the meaning from electronics.  Rather than switching at a fixed threshold, hysteresis is used to raise the threshold on the rising edge and lower the threshold on the falling edge.  This helps to avoid switching back and forth between two output states in the presence of input noise or oscillations.  This is a similar issue when deciding when to tag the detection of C flares when the background flux is very near the minimum C flare threshold.

I see now there is another definition of hysteresis (from economics) referring to an event that persists after the factors that led to that event have been removed.  Hysteresis could certainly be used to describe a returning AR, an active longitude, co-rotating interaction region, etc.

Edited August 17, 2021 by Drax Spacex

[Newbie]

I took you to mean there is as a lag between cause and observed effect. First a building up, then a spilling over. Sigmoid activity and increased solar flux is detected. This is the building up. The spilling over: a flare is produced and detected in SDO imagery. 

I'm so relieved we're good.....  Frank looks a whole lot scarier than the rabbit in the image 

 

Edited August 17, 2021 by Newbie

[Christopher S.]

On 8/16/2021 at 7:53 PM, Drax Spacex said:

Incidentally, when I used the word hysteresis, I was attempting to borrow the meaning from electronics.  Rather than switching at a fixed threshold, hysteresis is used to raise the threshold on the rising edge and lower the threshold on the falling edge.  This helps to avoid switching back and forth between two output states in the presence of input noise or oscillations.  This is a similar issue when deciding when to tag the detection of C flares when the background flux is very near the minimum C flare threshold.

I see now there is another definition of hysteresis (from economics) referring to an event that persists after the factors that led to that event have been removed.  Hysteresis could certainly be used to describe a returning AR, an active longitude, co-rotating interaction region, etc.

I would have understood it as the former, not even knowing the latter is an existing definition. TIL 👍 

[Drax Spacex]

2021-09-17 04:30:00 C5.5 flare off the southeast limb.  Location approximately S29E100.  No sunspots, no pores, no significant AR-like magnetogram structure visible on the solar disk.

But not too surprising as this is returning region 2860 which was very active the previous rotation.  In the past few days, Stereo A has shown increase flux, and LASCO has shown CMEs likely originating from this region.

The latest Solar Synoptic Map whole disk flare forecast now shows 25% C flare probability after this flare (up from 1%), even though the solar disk remains spotless.  So SWPC is accounting for recent limb activity, even without visible sunspots, which should improve flare prediction accuracy and timeliness.

Edited September 17, 2021 by Drax Spacex
Synoptic map discussion

[Archmonoth]

3 hours ago, Drax Spacex said:

2021-09-17 04:30:00 C5.5 flare off the southeast limb.  Location approximately S29E100.  No sunspots, no pores, no significant AR-like magnetogram structure visible on the solar disk.

But not too surprising as this is returning region 2860 which was very active the previous rotation.  In the past few days, Stereo A has shown increase flux, and LASCO has shown CMEs likely originating from this region.

The latest Solar Synoptic Map whole disk flare forecast now shows 25% C flare probability after this flare (up from 1%), even though the solar disk remains spotless.  So SWPC is accounting for recent limb activity, even without visible sunspots, which should improve flare prediction accuracy and timeliness.

Perhaps Corona perturbation? Since the radius of the Corona is larger than the opaque Sun, could the regions on the Synoptic map produce flares similar to lightning in a thunderstorm, from friction/tension between the 2 different radius? 

You mentioned the 2860 region. Perhaps an echo/left-over disruption in the Corona which can cause flares? 

Also, is this the Solar Synoptic map you are talking about? Solar Synoptic Map | NOAA / NWS Space Weather Prediction Center  

 

[Czort]

 

[Christopher S.]

2 hours ago, Czort said:

 

Someone was so excited to post about the flare on the 17th that they created a wormhole to the 27th and are posting from the future!

🤪

[Drax Spacex]

5 hours ago, Archmonoth said:

Perhaps Corona perturbation? Since the radius of the Corona is larger than the opaque Sun, could the regions on the Synoptic map produce flares similar to lightning in a thunderstorm, from friction/tension between the 2 different radius? 

You mentioned the 2860 region. Perhaps an echo/left-over disruption in the Corona which can cause flares? 

Also, is this the Solar Synoptic map you are talking about? Solar Synoptic Map | NOAA / NWS Space Weather Prediction Center  

 

Returning active regions are tracked from the previous rotation into the current rotation because they have a higher probability of remaining active (compared to a random area of the sun.)   I don't know what underlying theory may apply except momentum generally speaking.  But yes, nature likes to equalize things, so if there are disparities in nearby regions whether in magnetism, electrical charge, temperature, density, pressure, etc., yes I can see something like a lightning bolt, a flare, or a CME being the equalizer.

It easy to perceive that the sun is "scraping" on something along the limbs sparkling off lots of limb flares.  But there's a lot of surface area of the spherical sun concentrated near the limbs in our 2D projection viewpoint.  We would really need to look at the distribution of flare coordinates in longitude to know whether flares do have a higher frequency of occurrence near the limbs.

Yes, that's the live link for the most recently published SWPC Synoptic Map.  It seems to be currently stale though, either because of server-side or client-side caching, stuck on 16-Sep-21 0311Z with the 1% C flare probability.  I was using that one as a reference plus the next one published for 17-Sep-21 with a 25% C flare probability.

Edited September 17, 2021 by Drax Spacex
The Equalizer

[Newbie]

On 9/18/2021 at 6:17 AM, Czort said:

 

Czort, this is another good example of a flare occurring on the limb.

I hope that the sunspots will produce flares when they face Earth!

Thanks for posting it.

Newbie

[Drax Spacex]

Today we had an M1 flare from a region without sunspots - from plage region 2996 located at N25W53.

Product: Forecast Discussion :Issued: 2022 Apr 29 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity increased to moderate levels with an M1/1f (R1-Moderate) flare from plage Region 2996 (N25, L=067) observed at 29/0730 UTC.

That's pretty neat and very rare!