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Flare-Productive Active Regions


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There are magnetically complex regions that produce lots of solar flares like 5395 (β-γ-δ), 9393 (β-γ-δ), and 13664 (β-γ-δ).

In SC22, there exist only three very flare-productive active regions, 5395 (β-γ-δ), 5629 (β-γ-δ), and 6659 (β-γ-δ), that produced X21.5, X28.5 and X12+ flares, respectively.

In SC23, there exist only two very flare-productive active regions, 9393 (β-γ-δ), and 10486 (β-γ-δ), that produced X28.5 and X45 flares, respectively.

In SC24, there exist only one very flare-productive active region, 12192 (β-γ-δ), that produced an X4.5 flare.

In SC25, there currently exist only one very flare-productive active region, 13664 (β-γ-δ), that produced an X8.7 flare. (plus X12 on the farside)

Typical regions like 13659 (α) last for a short time but bigger regions like 13655 (β), 13648 (β-γ), and 13663 (β-γ-δ) last longer, but the biggest regions, like 13664 (β-γ-δ), tend to last the longest.

Here are some images for three flare-productive active regions from 1989 to 2024.

https://solarwww.mtk.nao.ac.jp/mitaka_solar/wl-fulldisk-photo/calendar/1989/jpg/wl19890311_001.jpg - 5395 (β-γ-δ)

wl19890311_001.jpg

https://www.spaceweatherlive.com/images/Archief/2003/Sunspots/sunspots_20031028.jpg - 10486 (β-γ-δ)

sunspots_20031028.jpg

https://www.spaceweatherlive.com/images/Archief/2024/Sun/20240511_HMIIF.jpg - 13664 (β-γ-δ)

20240511_HMIIF.jpg

So, how many flare-productive active regions are there per solar cycle?

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7 minutes ago, Patrick P.A. Geryl said:

X12 from 3664 on the Farside?

wasnt that old 3654?

Region 3664 would be the best fit. Region 3654 came to be 3686 on our side of the disk, while the flare occurred on the far side a few days later.

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Posted (edited)
40 minutes ago, Patrick P.A. Geryl said:

X12 from 3664 on the Farside?

wasnt that old 3654?

 

30 minutes ago, Jesterface23 said:

Region 3664 would be the best fit. Region 3654 came to be 3686 on our side of the disk, while the flare occurred on the far side a few days later.

Region 13664 (β-γ-δ) easily became the largest sunspot region of this solar cycle, at 2420 MSH on May 11 before the daily size was updated to 2400 MSH. Same goes for old 13590 (β-γ-δ) - 1550 vs 1450. Region 13664 (β-γ-δ) entered the farside on May 14th. The CME of the X12 flare occurred on May 20 on the farside when dangerous sunspot region 13664 (β-γ-δ) was on the farside.

Edited by faster328
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Just now, Jesterface23 said:

Juust keeping in mind, the farside flare strengths are estimations.

I estimate the farside X12 flare to rival the 2001 April 2 flare (X28.5) but unlikely to rival the 2003 November 4 flare (X45) - (greater than X15, no more than X30).

There are up to 15 flare-productive active regions per cycle (my estimate).

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53 minuten geleden, faster328 zei:

I estimate the farside X12 flare to rival the 2001 April 2 flare (X28.5) but unlikely to rival the 2003 November 4 flare (X45) - (greater than X15, no more than X30).

There are up to 15 flare-productive active regions per cycle (my estimate).

Was that X12 on June 1?

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Posted (edited)

The X12 was produced by 13664 (β-γ-δ) on the farside on May 20, 2024. But there are 6 X12+ flares produced by 6659 (β-γ-δ) from early-mid June of 1991.

Edited by faster328
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8 hours ago, faster328 said:

The X12 was produced by 13664 (β-γ-δ) on the farside on May 20, 2024. But there are 6 X12+ flares produced by 6659 (β-γ-δ) from early-mid June of 1991.

6659 is the king of big flares. Calling them X12+ flares is understating their true strength as four of them saturated the GOES x-ray sensors at just under X12 for many minutes and were certainly much higher. Additionally X12 back then is roughly equal to X17 now. All four of these flares were likely well above X20.

The strongest flare occurred on June 1 and may have been partially occulted as the region that would become 6659 would not become visible on the eastern limb until nearly 24 hours after this flare. The June 1 1991 flare is a top 3 flare of the past 40 years along with the Aug 16 1989 and Nov 4 2003 flares. Interestingly, all three of these flares occurred on or beyond the limb.

Edited by Aten
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7 hours ago, faster328 said:

I estimate the farside X12 flare to rival the 2001 April 2 flare (X28.5)

That might be pushing it. There is a possible range given of X6 to X25. It is likely more around X12, unless people that work with the Solar Orbiter look into it and release further information.

 

1 hour ago, Aten said:

6659 is the king of big flares. Calling them X12+ flares is understating their true strength as four of them saturated the GOES x-ray sensors at just under X12 for many minutes and were certainly much higher. Additionally X12 back then is roughly equal to X17 now. These all four of these flares were likely well above X20.

We don't know what the correction factor is for the GOES satellites back then are. They may be the same or different.

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48 minutes ago, Jesterface23 said:

We don't know what the correction factor is for the GOES satellites back then are. They may be the same or different.

Hmmm that's interesting if true, but if we know the correction factor for cycle 23 flares how could we not at least have a very good estimate of the factor for cycle 22? We have constant x-ray measurements, usually from more than one satellite, from the entirety of cycle 22 and 23. It seems kind of hard to believe we do not know how measurements from cycle 22 relate to measurements in cycle 23. I'm sure I have read a few papers discussing flares from both cycles 22 and 23, and I can't remember ever reading anything that would suggest an X flare in one cycle would not be the same as an X flare in the other cycle. I will have to look into this tomorrow when I have time.

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6 minutes ago, Aten said:

Hmmm that's interesting if true, but if we know the correction factor for cycle 23 flares how could we not at least have a very good estimate of the factor for cycle 22? We have constant x-ray measurements, usually from more than one satellite, from the entirety of cycle 22 and 23. It seems kind of hard to believe we do not know how measurements from cycle 22 relate to measurements in cycle 23. I'm sure I have read a few papers discussing flares from both cycles 22 and 23, and I can't remember ever reading anything that would suggest an X flare in one cycle would not be the same as an X flare in the other cycle. I will have to look into this tomorrow when I have time.

It will depend on if a different instrument used. That is pretty why the GOES X-ray data prior to GOES 16 is being updated.

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Posted (edited)

AR 6659 (β-γ-δ) is the king of superflares.

Note that 6659 (β-γ-δ) is the big region on the northeast/top left in the image of June 6, 1991 below:

wl19910606_001.jpg

Image source: https://solarwww.mtk.nao.ac.jp/mitaka_solar/wl-fulldisk-photo/calendar/1991/jpg/wl19910606_001.jpg

There are 6 X12+ (X17+) flares which one of them, the 1 June 1991 flare, saturated the X-ray sensors for about 10+ minutes.

7 hours ago, Jesterface23 said:

It will depend on if a different instrument used. That is pretty why the GOES X-ray data prior to GOES 16 is being updated.

Assume that the largest solar flare per solar cycle is affected by the size of the solar cycle.

For SC23, the 4 November 2003 flare is estimated to be about X45, as seen from Earth.

For SC10, the 1 September 1859 flare is estimated to be about X45 too, as seen from Earth.

For SC23 is larger than SC10, the actual size of the 4 November 2003 flare is about X55, if the flare occurred on the centre of the disk, compared to the 1 September 1859 flare's X50if the flare occurred on the centre of the disk.

If the largest solar flare per solar cycle is affected by the size of the solar cycle, then because of the size of SC22, the 1 June 1991 flare is the largest solar flare ever recorded since 1976, at X60if the flare occurred on the centre of the disk.

If the largest solar flare per solar cycle is affected by the size of the solar cycle, then because of the size of SC19, the 23 February 1956 flare is the largest solar flare ever recorded, at X100if the flare occurred on the centre of the disk.

Edited by faster328
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27 minutes ago, faster328 said:

AR 6659 (β-γ-δ) is the king of superflares.

Note that 6659 (β-γ-δ) is the big region on the northeast/top left in the image of June 6, 1991 below:

wl19910606_001.jpg

Keep in mind that in this instance the Sun's equator looks to be tilted clockwise by about 20-30 degrees.

 

36 minutes ago, faster328 said:

Assume that the largest solar flare per solar cycle is affected by the size of the solar cycle.

Maybe it can be assumed that way, but that isn't how it really works.

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7 hours ago, faster328 said:

For SC23, the 4 November 2003 flare is estimated to be about X45, as seen from Earth.

For SC10, the 1 September 1859 flare is estimated to be about X45 too, as seen from Earth.

Keep in mind that the papers containing these estimates were written during the time when the GOES estimates were still adjusted down 30%; today some of them even have explicit corrections in the publications, adjusting them up by the recriprocal factor of ~1.43 to X64 in both cases. These are of course just estimates in both cases anyway, but it's worth noting that those estimates are actually higher.

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19 hours ago, Jesterface23 said:

We don't know what the correction factor is for the GOES satellites back then are. They may be the same or different.

I am pretty sure I was correct in saying an X12 in 1991 measured by GOES 6 and 7 would be roughly X17 now.

"The operational XRS fluxes include scaling factors that were initially implemented by SWPC to get GOES-
8 to agree with GOES-7"

"To get true fluxes for GOES-1 through -15 operational data, users must remove the SWPC scaling
factors from the data. To do this, divide the short band flux by 0.85 and divide the long band flux by
0.7."

https://ngdc.noaa.gov/stp/satellite/goes/doc/GOES_XRS_readme.pdf

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1 hour ago, Aten said:

I am pretty sure I was correct in saying an X12 in 1991 measured by GOES 6 and 7 would be roughly X17 now.

"The operational XRS fluxes include scaling factors that were initially implemented by SWPC to get GOES-
8 to agree with GOES-7"

"To get true fluxes for GOES-1 through -15 operational data, users must remove the SWPC scaling
factors from the data. To do this, divide the short band flux by 0.85 and divide the long band flux by
0.7."

https://ngdc.noaa.gov/stp/satellite/goes/doc/GOES_XRS_readme.pdf

This is in section 2.2, so it seems a little more complicated.

"GOES-7 was the last of the spinning GOES satellites while GOES-8 was the first of the 3-axis-stabilized satellites."

"Since then rocket launches and comparisons with the new well-calibrated GOES-16 have confirmed that the GOES-8 through -15 sensors are accurate and that the use of scaling factors to match the old spinning satellites is not correct."

Here is the latest document if wanted as well.

https://www.ncei.noaa.gov/data/goes-space-environment-monitor/access/science/xrs/GOES_1-15_XRS_Science-Quality_Data_Readme.pdf

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40 minutes ago, Jesterface23 said:

This is in section 2.2, so it seems a little more complicated.

"GOES-7 was the last of the spinning GOES satellites while GOES-8 was the first of the 3-axis-stabilized satellites."

"Since then rocket launches and comparisons with the new well-calibrated GOES-16 have confirmed that the GOES-8 through -15 sensors are accurate and that the use of scaling factors to match the old spinning satellites is not correct."

Here is the latest document if wanted as well.

https://www.ncei.noaa.gov/data/goes-space-environment-monitor/access/science/xrs/GOES_1-15_XRS_Science-Quality_Data_Readme.pdf

If I'm not mistaken that's ultimately just saying that they adjusted the data 30% down to match GOES-7, whereas instead it was GOES-7 which should have been scaled up by the reciprocal of that (~1.43); so if I interpret it correctly then you should be getting the right values by adjusting the older satellites (up to GOES-7) up by the same factor, the difference being that GOES-8 though -15 actually measured the right values all along, while the earlier satellites measured the wrong values and actually did need to be corrected. There could be some details about the scaling factors of the earliest satellites that I'm not aware of though, like maybe they didn't agree perfectly with each other and that the 30% scaling factor of GOES-8 and beyond was more to match some average, not really sure. I guess the safest route would be to take some caution when it comes to the data from before GOES-8, while GOES-8 and beyond should be fairly safe to just remove the erroneous correction of.

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