From UCAR: Extended solar minimum linked to changes in Sun’s conveyor belt
BOULDER—A new analysis of the unusually long solar cycle that ended in 2008 suggests that one reason for the long cycle could be a stretching of the Sun’s conveyor belt, a current of plasma that circulates between the Sun’s equator and its poles. The results should help scientists better understand the factors controlling the timing of solar cycles and could lead to better predictions.
The study was conducted by Mausumi Dikpati, Peter Gilman, and Giuliana de Toma, all scientists in the High Altitude Observatory at the National Center for Atmospheric Research (NCAR), and by Roger Ulrich at the University of California, Los Angeles. It appeared on July 30 in Geophysical Research Letters. The study was funded by the National Science Foundation, NCAR’s sponsor, and by NASA’s Living with a Star Program.
The Sun goes through cycles lasting approximately 11 years that include phases with increased magnetic activity, more sunspots, and more solar flares, than phases with less activity. The level of activity on the Sun can affect navigation and communications systems on Earth. Puzzlingly, solar cycle 23, the one that ended in 2008, lasted longer than previous cycles, with a prolonged phase of low activity that scientists had difficulty explaining.
The new NCAR analysis suggests that one reason for the long cycle could be changes in the Sun’s conveyor belt. Just as Earth’s global ocean circulation transports water and heat around the planet, the Sun has a conveyor belt in which plasma flows along the surface toward the poles, sinks, and returns toward the equator, transporting magnetic flux along the way.
“The key for explaining the long duration of cycle 23 with our dynamo model is the observation of an unusually long conveyor belt during this cycle,” Dikpati says. “Conveyor belt theory indicates that shorter belts, such as observed in cycle 22, should be more common in the Sun.”
Recent measurements gathered and analyzed by Ulrich and colleagues show that in solar cycle 23, the poleward flow extended all the way to the poles, while in previous solar cycles the flow turned back toward the equator at about 60 degrees latitude. Furthermore, as a result of mass conservation, the return flow was slower in cycle 23 than in previous cycles.
In their paper, Dikpati, Gilman, and de Toma used simulations to model how the solar plasma conveyor belt affected the solar cycle. The authors found that the longer conveyor belt and slower return flow could have caused the longer duration of cycle 23.
The NCAR team’s computer model, known as the Predictive Flux-transport Dynamo Model, simulates the evolution of magnetic fields in the outer third of the Sun’s interior (the solar convection zone). It provides a physical basis for projecting the nature of upcoming solar cycles from the properties of previous cycles, as opposed to statistical models that emphasize correlations between cycles. In 2004, the model successfully predicted that cycle 23 would last longer than usual.
According to Dikpati, the duration of a solar cycle is probably determined by the strength of the Sun’s meridional flow. The combination of this flow and the lifting and twisting of magnetic fields near the bottom of the convection zone generates the observed symmetry of the Sun’s global field with respect to the solar equator.
“This study highlights the importance of monitoring and improving measurement of the Sun’s meridional circulation,” Ulrich says. “In order to improve predictions of the solar cycle, we need a strong effort to understand large-scale patterns of solar plasma motion.”
About the article
Title: Impact of changes in the Sun’s conveyor-belt on recent solar cycles
Authors: Mausumi Dikpati, Peter Gilman, Giuliana de Toma, and Roger Ulrich
Publication: Geophysical Research Letters
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This comment from spaceweather.com:
WEAK IMPACT: There was no green snow in Antarctica last night. The CME expected to hit Earth’s magnetic field on Aug. 17th either missed or delivered such a feeble blow that no one noticed the resulting geomagnetic disturbance. The next opportunity for auroras is Aug. 24th when an incoming solar wind stream could provoke polar geomagnetic storms. Stay tuned.
But isn’t it just as likely that the energy was absorbed into the ionosphere? We have been told that unusual conditions prevail that allows that to happen. So, if it didn’t show up on the surface, isn’t it likely its building up in the ionosphere?
katesisco says:
August 18, 2010 at 9:13 am
But isn’t it just as likely that the energy was absorbed into the ionosphere? We have been told that unusual conditions prevail that allows that to happen. So, if it didn’t show up on the surface, isn’t it likely its building up in the ionosphere?
No, because we have spacecraft out in front of the Earth way outside the ionosphere, and it didn’t see the CME either.
Leif Svalgaard says:
August 18, 2010 at 8:41 am (Edit)
tallbloke says:
August 18, 2010 at 5:29 am
As I said, Newton himself knew his equations of motion don’t apply to highly mobile fluid bodies like the Sun.
Yet gravity works to keep the gaseous Jupiter in orbit around the gaseous Sun. Gravity from the Moon and the fluid Sun raises the tides in the fluid oceans. Please, Newton’s laws are valid for all bodies.
The gross gravitational cApabilities are not at issue. Your poor understanding of Newton’s laws with respect to the angular momentum of rigid inelastic bodies is not at issue either. What is at issue is the fact that the Sun is anything but a rigid inelastic object. It’s a big hot wobbly ball of plasma and molten stuff, which has a highly irregular orbit only a couple of times its own diameter. This sets up differential forces across its sphere, even in a weightless environment where the sum total can be described correctly as freefall. And because it is a big wobbly ball of plasma which CAN’T TRANSMIT ALL THOSE DIFFERENTIAL FORCES INTERNALLY, waves will be set up which travel around its circumference. Any engineer with some knowledge of fluid mechnics should be able to tell you that.
tallbloke says:
August 18, 2010 at 9:44 am
What is at issue is the fact that the Sun is anything but a rigid inelastic object. It’s a big hot wobbly ball of plasma and molten stuff, which has a highly irregular orbit only a couple of times its own diameter. This sets up differential forces across its sphere
The last sentence is where you go wrong [apart from the nonsense that Newton’s law don’t apply universally]. The Sun is in free fall and does not feel any forces, just like an astronaut in the space station doing somersaults: http://il.youtube.com/watch?v=RjvmXLyrtjM&feature=related
Now, I know it is hopeless to educate you on this.
“Black hole mystery unveiled by magnetic star discovery”
http://www.bbc.co.uk/news/science-environment-11011118
“The discovery of a rare magnetic star – or magnetar – is challenging theories about the origin of black holes.”
Leif Svalgaard says:
August 18, 2010 at 10:02 am
tallbloke says:
August 18, 2010 at 9:44 am
What is at issue is the fact that the Sun is anything but a rigid inelastic object. It’s a big hot wobbly ball of plasma and molten stuff, which has a highly irregular orbit only a couple of times its own diameter. This sets up differential forces across its sphere.
The last sentence is where you go wrong [apart from the nonsense that Newton’s law don’t apply universally].
Newton’s laws (plural) apply universally to rigid, inelastic objects, just like he stated, but not to objects like the Sun. It’s easy to prove this with a Newtonian thought experiment, since you like those. Line up three pool balls touching each other. Now shoot a fourth directly at the front of the line. The ball stops dead and the back ball of the chain of four shoots off in the same direction with about the same velocity.
Now replace the centre ball with an equal mass of bread dough rolled into a ball. What happens is that the energy transmitted from the incoming ball is mostly lost in plasticly deforming the dough, and the back ball hardly moves away from the pack.
Now replace the centre ball with an elastic rubber ball. What hapens is the rubber ball deforms from the force transmitted by the front ball, and then springs back into shape, pushing the back ball on its way. Some energy is lost in the process as heat and inertial motion, so the back ball still doesn’t move away at the same rate as on the first occasion, and after a delay.
The Sun has strong surface gravity, so it will pull itself spherical again after the differential forces affecting it have an effect, like the rubber ball being squashed and rebounding. This is why the heliosiesmologists detect signals which coincide with subharmonic periods of planetary motions.
The Sun is in free fall and does not feel any forces.
Ah, back to the old mantra.
Now, I know it is hopeless to try to educate you on this….
I normally get the calculator hot on winter evenings when there is nothing better to do, but since I need to move forward with the hypothesis sooner than that, I’ll do the math and post it on my blog. Then you can demonstrate mathematically where I got it wrong, or accept that when it comes to knowledge about the fluid mechanics of elastic objects, you are thicker than a navvie’s butty.
By the way, your astronaut analogy doesn’t work because s/he is in orbit about his/her own centre of mass, unlike the Sun, which is in orbit about the centre of mass of the solar system, which includes the other objects in it.
there is no such thing as “physical law”, only theories which model what we observe
what we like to call “physical laws” do not apply universally, they approximate what we observe
newtons laws for example work great locally and as ideally simplified models which approximate our observations. but, i.e. , it is difficult to derive the advance of the perihelion of the orbit of mercury with them, and even then i have not heard of a derivation that matches observation. and newtons laws completely fail to describe what observe on scales larger than the solar system, or in complex systems. i.e. galactic rotation curves or tightly orbiting massive object. there are many more examples. newtons “laws” probably still apply in all these situations, but there is probably something else involved making a larger effect.
tallbloke says:
August 18, 2010 at 12:46 pm
Newton’s laws (plural) apply universally to rigid, inelastic objects, just like he stated
Show me where he stated that.
back ball still doesn’t move away at the same rate as on the first occasion, and after a delay.
This has nothing to do with Newton’s laws of motion: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html
The Sun has strong surface gravity, so it will pull itself spherical again after the differential forces affecting it have an effect
What differential forces? where do they come from? There are tidal forces from the distant planets, but they have no great effect. You seem to attach some significance to the notion that the orbit of the Sun has a size ‘only’ a few solar radii, as if the smaller the size, the bigger the effect. Can yo verify that for me? That you think it is the ‘tight’ orbit that does it? rather than if the orbit were huge.
Then you can demonstrate mathematically where I got it wrong
Newton did that centuries ago.
s/he is in orbit about his/her own centre of mass
The astronaut is in orbit about the Earth.
Leif Svalgaard says:
August 18, 2010 at 1:09 pm
You seem to attach some significance to the notion that the orbit of the Sun has a size ‘only’ a few solar radii, as if the smaller the size, the bigger the effect. Can yo verify that for me? That you think it is the ‘tight’ orbit that does it? rather than if the orbit were huge.
I could refer you to one of Theodor L’s papers, but you won’t read it with any worthwhile level of diligence, so I won’t bother.
Basically, in a large orbit, the level of difference in the angular momenta of gridded measurement packets on the near and far sides of the object will be minimally different. In a tightly orbiting object whose radius of orbit changes rapidly (the Sun) the differences are significant.
The astronaut is in orbit about the Earth.
Let me know when you’ve finished farting about with frames of reference and then we’ll discuss it.
tallbloke says:
August 18, 2010 at 1:56 pm
Basically, in a large orbit, the level of difference in the angular momenta of gridded measurement packets on the near and far sides of the object will be minimally different. In a tightly orbiting object the differences are significant.
Sounds like complete voodoo. Where did you get that? The words are normally used in quantum-mechanical analysis of molecules.
Tidal effects [and angular momemta] are larger, the larger the difference in distance between the near and far sides is. The tighter [smaller] the orbit is, the smaller are these effects, disappearing completely when the size has shrunk to zero.
Perhaps T.L. had something backwards here.
and then we’ll discuss it
sounds very much like the anguish from someone backed into a corner. Come out and face it.
tallbloke says:
August 18, 2010 at 12:46 pm
Newtonian thought experiment, since you like those. Line up three pool balls touching each other. Now shoot a fourth directly at the front of the line. The ball stops dead and the back ball of the chain of four shoots off in the same direction with about the same velocity.
Try using a little english on your cue ball and that stop dead thing wont happen Tallbloke. Not a good way for you to be left for the next shot. I mean I mean laid up next to your object ball and all like that. Things getting heavyy around here again.
for the record i find both leif’s and tallbloke’s work very interesting.
I take leif’s main point as that known magnetic forces operating in/on the sun dwarf in size the gravitational effects in/on the sun of any planetary or solar movements.
the above assertion is noncontroversial as far as said forces are calculated.
what remains uknown is how the sun actually operates. that’s a large unkown.
it could be possible that very small changes in the sun caused by sundry gravitational effects have a disproportionate effect relative to their size. why not keep looking into it?
even if the specific dynamo model advocated by leif turns out to match observation for intsance, the dynamo itself still lacks an explanation…how is it generated, why and how is it cyclical?
peterhodges says:
August 18, 2010 at 4:38 pm
even if the specific dynamo model advocated by leif turns out to match observation for instance, the dynamo itself still lacks an explanation…how is it generated, why and how is it cyclical?
The basic physics is the ‘induction equation’. The model is described nicely by Choudhuri and colleagues: http://www.physics.iisc.ernet.in/~arnab/prl.pdf , An alternative mdel that will also work is http://www.leif.org/research/Percolation%20and%20the%20Solar%20Dynamo.pdf
peterhodges says:
August 18, 2010 at 4:38 pm
why and how is it cyclical?
The Riga experiment might provide some clues.
“Scientists in Riga at the Institute of Physics at the University of Latvia are continuing to work on a much more physical mock-up of the core.
Their model consists of two concentric steel cylinders, three metres high and 80 centimetres in diameter, filled with molten sodium.
A propeller drives the sodium down through the inner cylinder in a helical flow.
The metal returns up the outer cylinder, and electric currents create a magnetic field.
“Sodium has – by a factor of 50 – better electro-conductivity,” the University’s Dr Agris Gailetis told Science In Action. “Sodium is moving 10,000 times faster.
“But of course our system is much, much smaller… but altogether, these factors are making our experiment not very different from conditions inside the Earth.”
However, bizarrely, the oscillations that the Riga experiment have produced have been found to be more like the regular 22-year-variations in the Sun, rather than the random ones in the Earth.
The reality of the core remains far more complex than concentric cylinders. The flow there is probably turbulent and chaotic.
“The Riga experiment didn’t, per se, undergo reversal,” said Dr Andy Jackson, who specialises in computer models at Leeds University in the UK.
“But it does generate a magnetic field which is oscillatory – but it’s oscillatory in a very regular sense, whereas the Earth is more of a random process.” ”
My bold, note the precedence.
peterhodges says:
August 18, 2010 at 4:38 pm
it could be possible that very small changes in the sun caused by sundry gravitational effects have a disproportionate effect relative to their size. why not keep looking into it?
Why not indeed? Especially when all the tantalising near correlations keep popping out. That’s what my blog is all about, emerging ideas for sharing and developing.
RE: Leif Svalgaard says: (August 18, 2010 at 10:02 am) “The Sun is in free fall and does not feel any forces, just like an astronaut in the space station doing somersaults…”
While this is true, the Sun is subject to minor tidal forces that vary with the degree of planetary conjunction and powerful dynamic internal forces that all have a zero net sum relative any other celestial body.
Leif Svalgaard says: (August 18, 2010 at 10:02 am) “The Sun is in free fall and does not feel any forces, just like an astronaut in the space station doing somersaults…”
Saying something is in free fall is not the same as saying there are no forces acting upon it, and you should know that as a physicist. Just as the Sun exerts tidal forces on each planet, each planet exerts tidal forces upon the Sun, which both distort its shape and cause it to orbit around a common center of mass. Without these movements that planets exert upon their primaries, astronomers would not be able to detect planets orbiting other stars.
That the center of mass is displaced from the Sun’s center of gravity, and the Sun’s gravity imposes a rather significant relativistic distortion upon local timespace, there will be frame dragging effects imposed upon the sun’s conveyor system.
Svalgaard,
“What differential forces? where do they come from? ”
I’m not commenting on what tailbloke has in, but you are missing a key difference between classical gravity and GR. An extended body like the sun in a dynamic solar system will experience differential forces. A big difference between Newtonian gravity and general relativity is that in the former the gravity field is instantaneous and in GR gravity propagates at the speed or light or slower. The sun is more than 4 light seconds in diameter, so different parts of the sun will be experiencing gravity from the planets when they were at different positions, not from the same position instanteously. We’ve discussed this before.
Spector [and others] says:
August 19, 2010 at 7:34 am
While this is true, the Sun is subject to minor tidal forces that vary with the degree of planetary conjunction and powerful dynamic internal forces that all have a zero net sum relative any other celestial body.
these effects are well known and can be accurately calculated. They are tiny, tiny, tiny. The tidal bulge caused by Jupiter is 0.4 millimeter [about 1/64th of an inch] high.
I don’t know what ‘powerful dynamic internal forces’ you are talking about, but there are powerful forces related to the convection of solar material, that overturns Texas-sized chunks at speeds of 500,000 millimeters per second.
http://chandra.harvard.edu/xray_astro/dark_matter/index.html
The nature of dark matter is unknown. A substantial body of evidence indicates that it cannot be baryonic matter, i.e., protons and neutrons. The favored model is that dark matter is mostly composed of exotic particles formed when the universe was a fraction of a second old. Such particles, which would require an extension of the so-called Standard Model of elementary particle physics, could be WIMPs (weakly interacting massive particles), or axions, or sterile neutrinos.
Enjoyed this Smackdown UFC bout. Some truly withering put-downs.
‘…..The tidal bulge caused by Jupiter(on the sun) is 0.4 millimeter [about 1/64th of an inch] high…’
I’m not sure you could measure the tidal bulge in my bath when I get in it to this degree of accuracy let alone the Jupiter’s effect on the Sun. I’m not a Scientist though…but this doesn’t seem to jive.
Looking forward to Tallbloke posting his recent musings over here at WUWT.
We will see if the sandcastle can with stand being peed on from a great height. Leif
reminds me of the guy who gets hauled in from the swimming pool by the life guard into the office
Life Guard: …..”You are banned because you deliberately peed in the pool”
Leif: “…But it was an accident!”
Life Guard: ..”Off the HIGH BOARD!!!”
johnnythelowery says:
August 21, 2010 at 2:17 pm
I’m not sure you could measure the tidal bulge in my bath when I get in it to this degree of accuracy let alone the Jupiter’s effect on the Sun. I’m not a Scientist though…but this doesn’t seem to jive.
You are correct that one could not measure a 0.4 millimeter tidal bulge on the Sun [that is, of course, the whole point] because it is so very tiny. But one can calculate how large it should be. Already Isac Newton knew how to do this. An approximate formula is bulge = (mass Jupiter/mass Sun) * (radius Sun /distance Sun to Jupiter)^3 * (radius Sun). Insert numbers and you get the 0.4 millimeter. If you use the Moon-Earth system, the formula yields 368 millimeter, a thousand times as large. The reasons for the three factors in the formula are:
1st: the bigger the mass of Jupiter, the larger the bulge
2nd: the further away Jupiter is, the smaller the bulge [gravity falls of as inverse square of distance, which means that differences in gravity fall of as the inverse cube
3rd: the wider the sun is, the larger the bulge
Well….amazing. ….and Thanks. Hope you were amused by my prior post. How did SHINE go? Anything stand out?
johnnythelowery says:
August 21, 2010 at 4:39 pm
Hope you were amused by my prior post.
No.
SHINE: http://shinecon.org/ViewUsBySessions10.php
No? My apologies then. I value this site because of the quality of people here like yourself and enjoy the back and forth even if it’s well over my head. Anyway, here’s a joke which involves physics of a sort….
‘… long time ago, Britain and France were at war. During one battle, the French captured an English colonel. They took him to their headquarters, and the French general began > to question him. Finally, as an after thought, the French general asked, “Why do you English officers all… wear red coats? Don’t you know the red material makes you easier targets for us to shoot at?”..
In his bland English way, the officer informed the general that the reason English officers wear red coats is so that if they are shot, the blood won’t show, and the men they are leading won’t panic. And that is why, from that day to …this,
all French Army officers wear brown pants!..