Flares, Longitudes, and Limbs (oh my!)

[Drax Spacex]

Much of the major flare (strong C, M, and 1 X) activity we've seen recently has occurred near the east limb or west limb of the Sun.  They seem to be occurring more often than would be expected if the flare locations were randomly distributed.

After a bit of research, I found two phenomenon, the Active Longitude, and a 24-day period between major flares, that could explain why we're seeing so many flares recently concentrated near the limbs.  Or more precisely, not to explain why they are occurring near the limbs, but to explain why they are occurring in the same place so frequently.

I would suggest that we have been in a phase where the Active Longitude from the earth view happens to be near a limb (and a subordinate Active Longitude perhaps 180° from the primary Active Longitude at the other limb).

However, since the latitude-dependent rotation period of the Sun (averaging 28 days) is slower than a 24-day major solar flare period, with a constant Heliographic coordinate Active Longitude (in Heliographic Coordinates) we should see a drift of Earth-viewed longitudinal concentration of flares to other longitudes (in Stonyhurst Heliographic Coordinates) away from the limbs.

References:

Active Longitude (60% of flares are located within +/- 36° from the active longitude in Heliographic coordinates):
https://ui.adsabs.harvard.edu/abs/2016ApJ...818..127G/abstract
https://ssg.group.shef.ac.uk/progress/dissemination/ESWW2015_Gyenge_belgium_V3.key.pdf

24-day period between major flares:
https://ui.adsabs.harvard.edu/abs/2004cosp...35.1395T/abstract

Edited July 11, 2021 by Drax Spacex
slower not faster

[Newbie]

3 hours ago, Drax Spacex said:

We should see a drift of Earth-viewed longitudinal concentration of flares to other longitudes (in Stonyhurst Heliographic Coordinates) away from the limbs.

 

I certainly hope so, because as you say, all the noteworthy activity has occurred on, before, or past the limbs.

We saw this earlier today with 2840. It did nothing at all until it reached the limb then it erupted with a C6 and C7 flare in quick succession and then a C4 for good measure!

Let's hope all the activity occurs on the earth facing side of the sun, that we're not left with sunspot graveyards - faculae and plages: a spotless sun. 😃

Edited July 10, 2021 by Newbie

[abc]

I would like to ask about the cause for the temporary enhancement of proton fluxto 0.967 pfu today. Several enhancements, though weaker can also be observed afterwards). Is that diue to  just natural fluctuations or other reasons 

Edited July 10, 2021 by abc

[Vancanneyt Sander]

SC24 also had a lot of limb flares if I remember correctly. 

the minor proton enhancement was due to the C-flares of yesterday, EPAM also recorded an SEP event

[abc]

what odes SEP mean

[Vancanneyt Sander]

SEP = solar energetic particles 

[Newbie]

Just as an aside, there is a very helpful topic: Acronyms and Abbreviations in the drop down menu of the Help tab at the top of the SWL home page. 

You guys have thought of everything on this website. 

Many thanks

 

[Drax Spacex]

For flares on the limbs to move to directly earth-facing (or directly behind on the far side) would require a 90° rotation.  Every solar rotation of 28 days minus the presumed major solar flare period of 24 days equals 4 days.  4 days of solar rotation = (4/28)*360 degrees = 51 degrees.  So every solar rotation, there should be an apparent 51° movement from an Earth view of the longitude where major solar flares occur.

For directly Earth-facing: 90 deg 90/51=1.82 solar rotations*28days/solar rotation=51 days.
For -30 degrees of directly Earth-facing, (90-30)/51=1.18 solar rotations*28=33 days.
For +30 degrees of directly Earth-facing,
(90+30)/51=2.34 solar rotations*28=65.9 days.

So I would guess between 33 and 66 days from now, centered on 51 days, we should see some major (strong C, M, or X) earth-facing solar flares positioned between +/-30 degrees longitude (Stonyhurst Heliographic Coordinates).

33 days = Friday, Aug 13, 2021
51 days = Tues, Aug 31, 2021
66 days = Wed, Sept 15, 2021

If this ends up being correct, it would be mostly a lucky guess, loosely based on presumptive recurrences of previously observed trends.

If this ends up being wrong, sufficient time will have passed that this prediction and this topic will have been blissfully forgotten 😉 .

[Archmonoth]

10 hours ago, Drax Spacex said:

For flares on the limbs to move to directly earth-facing (or directly behind on the far side) would require a 90° rotation.  Every solar rotation of 28 days minus the presumed major solar flare period of 24 days equals 4 days.  4 days of solar rotation = (4/28)*360 degrees = 51 degrees.  So every solar rotation, there should be an apparent 51° movement from an Earth view of the longitude where major solar flares occur.

For directly Earth-facing: 90 deg 90/51=1.82 solar rotations*28days/solar rotation=51 days.
For -30 degrees of directly Earth-facing, (90-30)/51=1.18 solar rotations*28=33 days.
For +30 degrees of directly Earth-facing,
(90+30)/51=2.34 solar rotations*28=65.9 days.

So I would guess between 33 and 66 days from now, centered on 51 days, we should see some major (strong C, M, or X) earth-facing solar flares positioned between +/-30 degrees longitude (Stonyhurst Heliographic Coordinates).

33 days = Friday, Aug 13, 2021
51 days = Tues, Aug 31, 2021
66 days = Wed, Sept 15, 2021

If this ends up being correct, it would be mostly a lucky guess, loosely based on presumptive recurrences of previously observed trends.

If this ends up being wrong, sufficient time will have passed that this prediction and this topic will have been blissfully forgotten 😉 .

 

My humble suggestion is to assign a certainty amount to your prediction, like 40% 30%? 

 

Also 66 days is a decent time to predict a C, M, or X flare in the area you suggest. From my perspective, a 66 day streak of non activity during Solar Cycle 25, is unlikely. I would give a 10% for a 66 steak of non-activity, or a 90% of an X,M,C flare within the 66 day period you mentioned. This credence is based on daily visitations of this site. 

 

I like the 51 degrees, and in a non-Space Weather related note, most of the pyramids are built at a 51 degree angle. The Bent Pyramid is an example of the errors in Pyramid building; changing angles due to other considerations. 

 

 

Edited July 11, 2021 by Archmonoth

[Drax Spacex]

6 hours ago, Archmonoth said:

My humble suggestion is to assign a certainty amount to your prediction, like 40% 30%? 

Yes that would be appropriate if I knew what probability to assign 😉 .  Those dates I cite could be considered a span of local maxima of probability (of unknown value), certainly not deterministic.  As for the 51° and pyramid association, if I could work in the golden ratio phi into this, we might really be onto something!

A visual model that comes to mind is the 1980 arcade video game Star Castle.  In it, there are multiple rotating concentric circles with notches, and when those notches (openings) line up, a flare erupts.  What also comes to mind is the operation of a combination lock but with multiple notches per wheel. https://youtu.be/D6DkKPy3Q_I

The concentric circles could be likened to the layers of the sun, or they could be considered layers of probability.  For example the outer layer could be probability based on Active Region sunspots, as in current Synoptic maps.  This probability could then be modulated by a second probability layer based that AR sunspot proximity to the Active Longitude.  A third probability layer could be temporal proximity to the 24-day major flare period.

Ultimately some kind of machine learning algorithm could sort this out with appropriate weighting to each of the probability factors.  The prerequisite, however, is the intelligence of scientists to research and identify which factors are relevant.

 

[Christopher S.]

45 minutes ago, Drax Spacex said:

Ultimately some kind of machine learning algorithm could sort this out with appropriate weighting to each of the probability factors.  The prerequisite, however, is the intelligence of scientists to research and identify which factors are relevant.

I wouldn't be so quick to assume so. There may be advancements in various quantum fields and new discoveries to be made before a computer can even remotely discern the variables at play. 

 

[Newbie]

On 7/10/2021 at 8:51 AM, Drax Spacex said:

Much of the major flare (strong C, M, and 1 X) activity we've seen recently has occurred near the east limb or west limb of the Sun.  They seem to be occurring more often than would be expected if the flare locations were randomly distributed.

After a bit of research, I found two phenomenon, the Active Longitude, and a 24-day period between major flares, that could explain why we're seeing so many flares recently concentrated near the limbs.  Or more precisely, not to explain why they are occurring near the limbs, but to explain why they are occurring in the same place so frequently.

I would suggest that we have been in a phase where the Active Longitude from the earth view happens to be near a limb (and a subordinate Active Longitude perhaps 180° from the primary Active Longitude at the other limb).

However, since the latitude-dependent rotation period of the Sun (averaging 28 days) is slower than a 24-day major solar flare period, with a constant Heliographic coordinate Active Longitude (in Heliographic Coordinates) we should see a drift of Earth-viewed longitudinal concentration of flares to other longitudes (in Stonyhurst Heliographic Coordinates) away from the limbs.

References:

Active Longitude (60% of flares are located within +/- 36° from the active longitude in Heliographic coordinates):
https://ui.adsabs.harvard.edu/abs/2016ApJ...818..127G/abstract
https://ssg.group.shef.ac.uk/progress/dissemination/ESWW2015_Gyenge_belgium_V3.key.pdf

24-day period between major flares:
https://ui.adsabs.harvard.edu/abs/2004cosp...35.1395T/abstract

Interesting information.

With regards to the paper you mention: Temmer et al, Harvard 2004, '24 day period between major flares' I note the research was conducted over 2 solar cycles 21 and 22, but then applied retrospectively to cycles 19 and 20.

Do you know if their or other work continues to this day and if the conclusions were able to be applied to cycles 23 and 24?

Additionally, do you know what constituted a major flare? M class and above?

Ahh! Golden ratios keep popping up! (Maybe) Love it!

[Drax Spacex]

The 2004 paper about the 24-day period defined a major flare as having "H-alpha flare (importance >= 1)" where importance has a range between 0 and 3.  Back in the day, this was one of the parameters used to characterize a solar flare.  I don't know how that maps to the modern A,B,C,M,X classifications.

Yes there are some interesting papers on this topic.  I don't know if their work continued, but do post the links if you find additional papers.  For the papers I found, I used the web search "solar flare frequency of occurrence by longitude". There maybe some more recent or more definitive papers, or papers that more pointedly address the frequency of occurrence of limb flares.

[Newbie]

Yeah I see your point re H-alpha classifications. 

My understanding is they were qualitative and flares were classified as faint, normal or brilliant, whereas A, B, C, M & X are quantitative, they can be measured, and refer to the number of x ray photons passing through the satellite sensors over time.

[Newbie]

On 7/10/2021 at 8:51 AM, Drax Spacex said:

Much of the major flare (strong C, M, and 1 X) activity we've seen recently has occurred near the east limb or west limb of the Sun.  They seem to be occurring more often than would be expected if the flare locations were randomly distributed.

After a bit of research, I found two phenomenon, the Active Longitude, and a 24-day period between major flares, that could explain why we're seeing so many flares recently concentrated near the limbs.  Or more precisely, not to explain why they are occurring near the limbs, but to explain why they are occurring in the same place so frequently.

I would suggest that we have been in a phase where the Active Longitude from the earth view happens to be near a limb (and a subordinate Active Longitude perhaps 180° from the primary Active Longitude at the other limb).

However, since the latitude-dependent rotation period of the Sun (averaging 28 days) is slower than a 24-day major solar flare period, with a constant Heliographic coordinate Active Longitude (in Heliographic Coordinates) we should see a drift of Earth-viewed longitudinal concentration of flares to other longitudes (in Stonyhurst Heliographic Coordinates) away from the limbs.

References:

Active Longitude (60% of flares are located within +/- 36° from the active longitude in Heliographic coordinates):
https://ui.adsabs.harvard.edu/abs/2016ApJ...818..127G/abstract
https://ssg.group.shef.ac.uk/progress/dissemination/ESWW2015_Gyenge_belgium_V3.key.pdf

24-day period between major flares:
https://ui.adsabs.harvard.edu/abs/2004cosp...35.1395T/abstract

It seems that AR2842 is going to follow the same pattern, it has grown in size and complexity as it approaches the west limb. 

25% C flare, 5% M flare!

[Drax Spacex]

We will soon see!  As these AR region flare probabilities increase, it's more of a heightened alert to keep an eye on them.  As we saw with the recent X1 flare, flares can happen even with low probability; or inversely, not happen with high probability.  Whoever can accurately and reliably predict when and where solar flares of a given intensity will occur will win a Nobel Prize (and a pat on the back).

AR2842 has been a bit unusual because of its magnetic orientation.  Normally we see horizontal +/- or -/+ polarity regions in the magnetogram, but for AR2842 it has been more vertical (or it was a few days ago, now it's more diagonal).

We did see a C1.29 limb flare yesterday behind the east limb, just north and east of AR2847.  So the trend continues it seems - though those recent big blasts on the far side were certainly away from the limbs.

Edited July 21, 2021 by Drax Spacex
2827>2847

[Newbie]

Funny that you mention magnetic orientations, polarities and so on, I've been trying to get my head around this very thing. That is why I mistakenly thought an SC25 spot was configured like an SC24 spot, in another post, when obviously it wasn't. Yeah I know there's nothing magic going on with this limb activity, I just thought it interesting how AR2842 has developed. 

Also mourning the fact that all the interesting solar activity has been out of our view on the far side of the sun and is likely to continue that way. That C1.29 flare must have been behind the limb as I can't see it attributed to any numbered region. Here's hoping for some earth facing flares soon. 

 

[Isatsuki San]

3 hours ago, Drax Spacex said:

¡Pronto veremos! A medida que aumentan las probabilidades de que se produzcan erupciones en la región de RA , vigilarlas es más una alerta elevada. Como vimos con la reciente erupción X1, las erupciones pueden ocurrir incluso con baja probabilidad; o al revés, no suceda con alta probabilidad. Quien pueda predecir con precisión y fiabilidad cuándo y dónde ocurrirán las erupciones solares de una intensidad determinada, ganará un Premio Nobel (y una palmada en la espalda).

AR2842 ha sido un poco inusual debido a su orientación magnética. Normalmente vemos regiones de polaridad horizontal +/- o - / + en el magnetograma, pero para AR2842 ha sido más vertical (o lo era hace unos días, ahora es más diagonal).

Ayer vimos un destello en el limbo C1.29 detrás del limbo este, justo al norte y al este de AR2847. Así que, al parecer, la tendencia continúa, aunque esas grandes explosiones recientes en el otro lado ciertamente estuvieron lejos de las extremidades.

If they were far from the longitude, but it makes sense since that part of the sun always caused the sunspots to make big eruptions like those of 2012 cme carriptong good for me it is like that,

[Newbie]

11 hours ago, Drax Spacex said:

We will soon see!  As these AR region flare probabilities increase, it's more of a heightened alert to keep an eye on them.  As we saw with the recent X1 flare, flares can happen even with low probability; or inversely, not happen with high probability.  Whoever can accurately and reliably predict when and where solar flares of a given intensity will occur will win a Nobel Prize (and a pat on the back).

AR2842 has been a bit unusual because of its magnetic orientation.  Normally we see horizontal +/- or -/+ polarity regions in the magnetogram, but for AR2842 it has been more vertical (or it was a few days ago, now it's more diagonal).

We did see a C1.29 limb flare yesterday behind the east limb, just north and east of AR2847.  So the trend continues it seems - though those recent big blasts on the far side were certainly away from the limbs.

There we have it, AR2842 is now beta-gamma! 

[Drax Spacex]

If I were a betting man, I would place a $10 craps bet on AR2842 "Limb Flare".  

[Newbie]

21 hours ago, Drax Spacex said:

If I were a betting man, I would place a $10 craps bet on AR2842 "Limb Flare".  

So glad you're not a betting man Drax Spacex! I bet you are as wel!! 😁

Who can know the way of our Sun!

[Drax Spacex]

On 7/11/2021 at 2:00 AM, Drax Spacex said:

For flares on the limbs to move to directly earth-facing (or directly behind on the far side) would require a 90° rotation.  Every solar rotation of 28 days minus the presumed major solar flare period of 24 days equals 4 days.  4 days of solar rotation = (4/28)*360 degrees = 51 degrees.  So every solar rotation, there should be an apparent 51° movement from an Earth view of the longitude where major solar flares occur.

For directly Earth-facing: 90 deg 90/51=1.82 solar rotations*28days/solar rotation=51 days.
For -30 degrees of directly Earth-facing, (90-30)/51=1.18 solar rotations*28=33 days.
For +30 degrees of directly Earth-facing,
(90+30)/51=2.34 solar rotations*28=65.9 days.

So I would guess between 33 and 66 days from now, centered on 51 days, we should see some major (strong C, M, or X) earth-facing solar flares positioned between +/-30 degrees longitude (Stonyhurst Heliographic Coordinates).

33 days = Friday, Aug 13, 2021
51 days = Tues, Aug 31, 2021
66 days = Wed, Sept 15, 2021

If this ends up being correct, it would be mostly a lucky guess, loosely based on presumptive recurrences of previously observed trends.

If this ends up being wrong, sufficient time will have passed that this prediction and this topic will have been blissfully forgotten 😉 .

Finally some Earth-oriented flares 
within -/+ 30° longitude.

Three C flares from today:
2021-08-26 18:18 2859 N16E06 C3.0
2021-08-26 19:01 2860 S30E14 C1.3
2021-08-26 23:22 2860 S30E14 C4.0

Is this evidence that the Active Longitude has become "unstuck" from the limbs and has now rotated to be more Earth-facing (at least through the middle of next month)?  Or are these three flares merely random, coincidental data points?

What would an application of the scientific method tell us?

Edited August 27, 2021 by Drax Spacex
Updated from two to three C flares

[Christopher S.]

15 hours ago, Drax Spacex said:

What would an application of the scientific method tell us?

I think non-discretionary evaluation of sunspots, in terms of longitude, would be neat, although since the plane of action is rotating, the core underneath is rotating in a different manner, and we're revolving around it, the observation gets an extra layer of subjectivity due to the relative perspectives as opposed to charting the sunspots based on latitude, which is a lot simpler. So, the scientific method right now would tell us that the longitude of flares and sunspots are fairly random, with potential outliers in averaged data worth taking a look at. Again, however, I feel that the factors directly involved here require an assortment of accurate data in terms of the solar dynamics, in addition to having a 360º observation radius of the Sun.

Really wishing we get a "SURROUND" sequel to the STEREO program

[Drax Spacex]

There was a span of years (2011-2014) when Stereo A and B were both operational and positioned relative to the Sun and the Earth (SDO) to provide complete 360° views of the Sun.  Ah, those were the days!

The scientific method says to me that the results of a single iteration of an experiment do not prove or disprove a hypothesis.  This is especially true when the hypothesis proposes an enhanced probability not a deterministic result.  Hundreds of iterations would be appropriate, both retrospective and prospective.

Be skeptical, as should be your audience. Do not expect others to accept your assertions on faith.  Expect them to ask you to "Show me, don't tell me."

• State your hypothesis.
• Define the event data to be recorded during the experiment.
• Choose the date range for the experiment.
• Document your scoring method defining what is a hit and what is a miss with respect to your hypothesis.
• Objectively record all event data for the duration of your experiment, both hits and misses.  Do not cherry-pick only the observations that support your hypothesis.
• Report your scoring results
• Discuss your observations and conclusions
• Refine your hypothesis
• Shampoo, Rinse, Repeat

[Newbie]

2 hours ago, Drax Spacex said:

There was a span of years (2011-2014) when Stereo A and B were both operational and positioned relative to the Sun and the Earth (SDO) to provide complete 360° views of the Sun.  Ah, those were the days!

Ahh yes, those halcyon days! the days where nothing else mattered while we could still view 360º of the Sun.

Zoom to now

It turns out Hubble never once espied STEREO B, (wipes egg off face, avoiding newly shampooed and rinsed hair x 2), but and here's the good bit: sometime in 2022 STEREO B will make its closest approach to Earth and still there is hope, like the Phoenix rising from obscurity, STEREO B may once again join with its doppelganger and rule the heavens returning to us what is rightfully ours:  360º.

Newbie 

Edited August 30, 2021 by Newbie
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