“white light” solar flares

[hamateur 1953]

These mysterious high energy events have been witnessed twice that I am aware of  The 1859 Carrington event  And the Aug 4 1972 event.  Why do I bring this up now?  Well, I am hoping as all of us here are to see a repeat this cycle if we are lucky.  1972 went into the gamma region ( very rare) and was recorded as having produced this type of event   We were unfortunately unlucky in bz that day and it only produced high level activity for an hour or so.  This cycle really seems interesting in many ways.  If anyone knows more about the white light accompanying high level flaring, please post here   Thanks  Mike/Hagrid 

 

 

 

 

[Nathan Majors]

What is the white light caused by if you know

[Aten]

White light flares have been seen much more than twice, I believe most big X-class flares produce white light flares as long as the sunspot is not hidden behind the limb.

Here is a paper that talks about three white light flares from region 6659 in 1991, probably most productive sunspot in terms of large flares.

https://articles.adsabs.harvard.edu/pdf/1992PASJ...44L...7S

If you look around I'm sure you can find many old papers and reports of white light flare observations. I think white light observations get less attention now because of all the high quality EUV images we have nowadays that show much more than a white light image.

 

[Vancanneyt Sander]

Another interesting read on white light flares: https://www.aanda.org/articles/aa/full_html/2011/06/aa15930-10/aa15930-10.html

[Aten]

The biggest flares are clearly visible in SDO's HMI images. For example you can see the X5 flare from 12/31/23

https://streamable.com/ox47fw

HMI observes the sun at the 6173 angstrom wavelength, so these are not true white light, but they should be very similar to broadband white light images.

Edited February 15 by Aten

[SpaceWeather5464]

2 hours ago, hamateur 1953 said:

These mysterious high energy events have been witnessed twice that I am aware of  The 1859 Carrington event  And the Aug 4 1972 event.  Why do I bring this up now?  Well, I am hoping as all of us here are to see a repeat this cycle if we are lucky.  1972 went into the gamma region ( very rare) and was recorded as having produced this type of event   We were unfortunately unlucky in bz that day and it only produced high level activity for an hour or so.  This cycle really seems interesting in many ways.  If anyone knows more about the white light accompanying high level flaring, please post here   Thanks  Mike/Hagrid 

 

 

 

 

White light flares are common not rare, Looking at SDO Intensitygram archive the X2.87 from Dec 14, 2023 was a white light flare, The X5 flare from Dec 31, 2023 was also a white light flare, The X9 flare from 2017 was also a white light flare. They seem to happen when a flare above X1 happens.

1 hour ago, Nathan Majors said:

What is the white light caused by if you know

White light flare is when a solar flare can be seen in visible light. Without the hydrogen alpha filter that most people use to see flares from a telescope.

[hamateur 1953]

2 hours ago, Vancanneyt Sander said:

Another interesting read on white light flares: https://www.aanda.org/articles/aa/full_html/2011/06/aa15930-10/aa15930-10.html

That was an excellent paper @Vancanneyt Sander Thanks. Especially as I learned that the X-17 ( or perhaps larger now) haha of Oct 28 2003 from 10486 ranked among the others.  Cool Stuff.  Mike.  Edit:   The updated calculations put it just over X-24. Wow. 

Edited February 15 by hamateur 1953
Checked revised archives

[Parabolic]

Cool fact about the 1972 CME: since it's magnetic orientation wasn't really all that compatible with Earths, when it hit it compressed the magnetosphere so hard and fast that it essentially produced the 3rd type of EMP. It hit the Midwest United States in a North East direction and was not a good day for the Bell Telephone Company. I think they have recordings of the Dawn Chorus from that day (I think that's correct term).

[hamateur 1953]

18 minutes ago, Parabolic said:

Cool fact about the 1972 CME: since it's magnetic orientation wasn't really all that compatible with Earths, when it hit it compressed the magnetosphere so hard and fast that it essentially produced the 3rd type of EMP. It hit the Midwest United States in a North East direction and was not a good day for the Bell Telephone Company. I think they have recordings of the Dawn Chorus from that day (I think that's correct term).

It is correct, and I heard Tamitha Skov mention it briefly. Unfortunately their “ Trunk” cabling ran very close in a parallel line to our magnetic field, permitting quite a bit of induction. She uses good analogies I think.  Hers in this case is the “ Bumper Car” effect. Like those fun rides when kids get to play adult and crash into each other.  Haha. 

Edited February 15 by hamateur 1953

[hamateur 1953]

I’d like to thank all that replied above btw @Aten @Parabolic @Nathan Majors @SpaceWeather5464  and encourage them to read the link, it is a bit deep, but worthwhile imo.  Mike/Hagrid