The “Race to the Poles”

[hamateur 1953]

I’ve heard many speak of this event or events before and definitely misunderstood its meaning.  I can find little mention of it searching around where most of us do these days.  It sounds pretty interesting from what little I have learned so far.  Any direction to good articles on the subject for a non scientist would be appreciated. Mike/Hagrid 

[AScaredObserver]

From what I did a quick Google search for... it's apparently something to do with expeditions to the geographical poles.

Am I missing something here?

[hamateur 1953]

27 minutes ago, AScaredObserver said:

From what I did a quick Google search for... it's apparently something to do with expeditions to the geographical poles.

Am I missing something here?

Yes. It's my fault actually.  I will try to elaborate to avoid any further confusion. Btw, you had the same difficulty I encountered!  As I have understood it, when we are near Solar Maximum in any SC. The sunspot pairs  may annihilate near the equator. Thus leaving essentially an orphan which is then conveyed to its respective pole.  At least, that is my current understanding of the process.  Mike   Edit:  I was hoping to witness a cool explosion sometime. Seems like It isn’t really all that big of a deal or I’d probably have heard more about those events.   

Edited January 16 by hamateur 1953
Waiting for X classes

[Newbie]

17 minutes ago, hamateur 1953 said:

Yes. It's my fault actually.  I will try to elaborate to avoid any further confusion. Btw, you had the same difficulty I encountered!  As I have understood it, when we are near Solar Maximum in any SC. The sunspot pairs  may annihilate near the equator. Thus leaving essentially an orphan which is then conveyed to its respective pole.  At least, that is my current understanding of the process.  Mike 

My take on race to the poles is that it is about the migration of magnetic fields towards the solar poles, once the terminator has been reached and pole reversal has taken place. 

https://www.scientificamerican.com/article/the-suns-magnetic-poles-are-vanishing/

Above is a Scientific American article below is an excerpt.

Each sunspot comes in a pair; one is magnetically positive, and the other is negative. These magnetic pairs mostly—but not entirely—dissipate as the sunspots decay away, leaving a little leftover magnetic flux of one charge or the other. This leftover magnetism is typically the opposite polarity of that of the solar hemisphere it appears on. And as material moves around the sun, these leftovers typically migrate toward the pole of that hemisphere, which usually cancels out a little of the existing magnetic field there.

The article goes on to describe its take on SC24 and hopes for the current SC.

N.

 

[hamateur 1953]

Ok then. Good article too!  Tnx @Newbie

[Drax Spacex]

15 hours ago, Newbie said:

https://www.scientificamerican.com/article/the-suns-magnetic-poles-are-vanishing/

Above is a Scientific American article below is an excerpt.

Each sunspot comes in a pair; one is magnetically positive, and the other is negative. These magnetic pairs mostly—but not entirely—dissipate as the sunspots decay away, leaving a little leftover magnetic flux of one charge or the other. This leftover magnetism is typically the opposite polarity of that of the solar hemisphere it appears on. And as material moves around the sun, these leftovers typically migrate toward the pole of that hemisphere, which usually cancels out a little of the existing magnetic field there.

The article goes on to describe its take on SC24 and hopes for the current SC.

N.

 

Interesting article, interesting concept, but is it fact or theory - the idea that the migrating residual magnetism of sunspots is what modulates the magnetic field at the poles?  Is it truly the prime mover of pole reversals?  Or is it just an effect, a consequence of an as-yet undiscovered prime mover cause?  Something that affects both sunspots and pole magnetism?

If "each sunspot comes in a pair; one is magnetically positive, and the other is negative" then where is the other magnetic polarity for alpha unipolar sunspot groups?  Below the surface I suspect.

[Philalethes]

17 minutes ago, Drax Spacex said:

If "each sunspot comes in a pair; one is magnetically positive, and the other is negative" then where is the other magnetic polarity for alpha unipolar sunspot groups?  Below the surface I suspect.

That's strictly speaking not possible to my knowledge; or at least it would violate one of Maxwell's equations, specifically Gauss's law for magnetism (it would essentially represent a magnetic monopole). The net flux must be zero for any closed surface (like e.g. the surface of a sphere, like the Solar surface), so any flux in a given direction out of the surface must have an equal flux in the other direction into it somewhere.

That being said, I don't know the extent to which the changes in flux in different locations on the surface over the course of a Solar cycle corresponds to the ideas mentioned above, but it's definitely a very interesting topic. It makes sense in a certain way, because the leading sunspots will be the ones of the same polarity as the pole of the corresponding hemisphere at the beginning of the cycle, and will be the ones closest to the equator, so as the flux migrates to the equator it's the following flux that would be "left behind", which would be of the opposite polarity that the hemisphere eventually turns into at the next minimum.

Then again, like you say, even if such a simplification were to be true, would that really mean one should consider that the underlying cause itself, or is all of that movement perhaps just the consequence of a more fundamental underlying cause? Personally I think that's more likely, and that some sort of dynamo model makes more sense to think about, but perhaps they might be two ways of looking at the same thing.

In any case, unless there are magnetic monopoles near the Solar surface, unipolar regions will have flux connecting to other areas, whether that be to spots in other regions or more dispersed to the point where it doesn't crop up in the magnetograms due to the thresholds for the imagery.

[Drax Spacex]

I don't know who frustrates invention with physical constraint more - Maxwell or Einstein!  True - the opposite magnetic polarity of alpha sunspots must exist somewhere, and yes it could exist as dispersed or distant flux.

The disintegration of ARs into wisps of magnetic flux flung in the direction of the poles can be readily seen in these movies:

https://gong.nso.edu/data/magmap/cr_movie.html

As an AR disintegrates, I don't see one polarity being absorbed more or less than the other in either hemisphere, though the tracking of the magnetic remnants becomes difficult over a few Carrington cycles in this qualitative graphical depiction.

[hamateur 1953]

I can trump both with R.P. Feynman or Niels Bohr.  And what are they actually doing when not under our observations. Ouch!   Sorry Drax just couldn’t resist. 

23 minutes ago, Drax Spacex said:

I don't know who frustrates invention with physical constraint more - Maxwell or Einstein!  True - the opposite magnetic polarity of alpha sunspots must exist somewhere, and yes it could exist as dispersed or distant flux.

The disintegration of ARs into wisps of magnetic flux flung in the direction of the poles can be readily seen in these movies:

https://gong.nso.edu/data/magmap/cr_movie.html

As an AR disintegrates, I don't see one polarity being absorbed more or less than the other in either hemisphere, though the tracking of the magnetic remnants becomes difficult over a few Carrington cycles in this qualitative graphical depiction.

 

Edited January 16 by hamateur 1953

[Philalethes]

33 minutes ago, Drax Spacex said:

I don't know who frustrates invention with physical constraint more - Maxwell or Einstein!  True - the opposite magnetic polarity of alpha sunspots must exist somewhere, and yes it could exist as dispersed or distant flux.

The disintegration of ARs into wisps of magnetic flux flung in the direction of the poles can be readily seen in these movies:

https://gong.nso.edu/data/magmap/cr_movie.html

As an AR disintegrates, I don't see one polarity being absorbed more or less than the other in either hemisphere, though the tracking of the magnetic remnants becomes difficult over a few Carrington cycles in this qualitative graphical depiction.

That's a really cool animation! When I turn it up really fast I think I can see one color predominate in the wisps, the one that the pole is turning into, especially towards the end of the cycle, but maybe I'm only imagining it due to expecting it to be there. At least you can see the colors at the poles themselves streaming by as they switch (in the beginning a white stream in the southern hemisphere and black stream in the the northern, switching over to the opposite over the course of SC24). Looks quite similar to the development seen in the frozen version on the HMI polar fields page (the bottom butterfly diagram), which I suppose is only to be expected.

Edited January 16 by Philalethes
typo

[Newbie]

11 hours ago, Drax Spacex said:

Interesting article, interesting concept, but is it fact or theory - the idea that the migrating residual magnetism of sunspots is what modulates the magnetic field at the poles?  Is it truly the prime mover of pole reversals?  Or is it just an effect, a consequence of an as-yet undiscovered prime mover cause?  Something that affects both sunspots and pole magnetism?

If "each sunspot comes in a pair; one is magnetically positive, and the other is negative" then where is the other magnetic polarity for alpha unipolar sunspot groups?  Below the surface I suspect.

I don’t believe the article puts forward the idea that this is the sole driver behind migration of magnetic fields or elements to the poles. It addresses the question asked in the topic thread 😊

After solar maximum, the Sun's magnetic activity undergoes complex processes as part of the solar cycle.
Magnetic flux transport to the solar poles is influenced by the Sun's differential rotation, which causes various layers of the Sun to rotate at different rates. The solar magnetic field is generated by this proposed solar dynamo process occurring in the convective zone.

As the Sun progresses from solar maximum to solar minimum, the overall magnetic activity decreases. The magnetic flux from active regions, such as sunspots, tends to migrate toward the solar poles due to the differential rotation. The process involves the advection of magnetic elements or fields by meridional flow and the action of the Coriolis effect.

Meridional flow refers to the poleward or equator-ward movement of plasma and magnetic fields on the solar surface. 

The Coriolis effect is a specific effect caused by the rotation of a body, affecting the apparent motion of objects in a rotating frame.

Near the solar equator, the Coriolis effect tends to deflect solar materials to the east (prograde motion).

At higher solar latitudes, the Coriolis effect contributes to a more complex interaction, affecting the behaviour of solar features like sunspots,  producing complex trajectories.

These complex trajectories are the varied and intricate paths followed by solar materials, such as plasma and magnetic fields, as they move within the Sun.

The Coriolis effect, resulting from the Sun's rotation, causes the motion of materials to be deflected. This deflection, combined with other solar processes, leads to complex and often non-uniform paths. Rather than following straight, predictable paths, solar materials experience curvilinear or meandering trajectories.

These complex trajectories are especially pronounced at higher solar latitudes, where the influence of the Coriolis effect is more significant.

Another effect is the tilting of sunspots according to Joy’s law.

Solar dynamo models in the past had been attributed to the winding up of the weaker poloidal field (from the poles to the equator or north south orientation) to create a much stronger toroidal field (east - west orientation). However, recent radio observations of relatively colder stars and brown dwarfs, which do not have a radiative core and only have a convection zone, have demonstrated that they maintain large-scale, solar-strength magnetic fields and display solar-like activity despite the absence of tachoclines.
The tachocline is a thin layer within the interior of the Sun, situated near the boundary between its convective outer layer and the radiative zone. This transition region, typically spanning a few percent of the Sun's radius, is characterised by a significant change in the rotation rate of the solar material.

This finding suggests that the convection zone alone may be responsible for the function of the solar dynamo and not also from areas deeper within the solar core…but there is still a lot of work to be done.

Advection is a transport process in fluid dynamics where a substance, such as a fluid or a specific property of the fluid (like heat or chemical components), is carried by the bulk motion of the fluid itself. It involves the transfer of mass, energy, or other properties from one location to another due to the movement of the fluid.
Advection, wrt magnetic flux transport on the Sun involves the movement of magnetic fields within the overall motion of the solar plasma, contributing to the redistribution of magnetic features across the solar surface.

During the declining phase of the solar cycle, the polar magnetic fields gradually strengthen as more magnetic flux is transported toward the poles. This transport is not a direct, simple flow; it involves the interaction of magnetic fields with the turbulent solar convection and differential rotation.

Observations show that the polar magnetic fields reach their maximum strength a few years after solar maximum.

N.

Edited January 17 by Newbie
Clarification

[arjemma]

I agree with all of you on this and I just wanted to add that you can google "solar cycle rush to the poles" to find a bunch of scientific articles about this.

A very simplified and short explanation is that in the decline of a solar cycle (after maximum) sunspots migrate from the equator and goes to the poles and then disappears from the surface of the sun. This can be seen in the butterfly diagram for example. The migration is thought to be mainly because of the underlying magnetism and differential rotation of the sun but can also be because of other factors.

Hopefully if we will be able to create a full 3D MHD (magnetohydrodynamic) model things like this might be more understood.