We’ve been watching the progress on the WUWT solar reference page in this plot from Dr. Leif Svalgaard:
Solar Polar Fields – Mt. Wilson and Wilcox Combined -1966 to Present
Leif Svalgaard – Click the pic to view at sourceNow, NASA has decided to call the flip. Video follows.
Something big is about to happen on the sun. According to measurements from NASA-supported observatories, the sun’s vast magnetic field is about to flip.
“It looks like we’re no more than 3 to 4 months away from a complete field reversal,” says solar physicist Todd Hoeksema of Stanford University. “This change will have ripple effects throughout the solar system.”
The sun’s magnetic field changes polarity approximately every 11 years. It happens at the peak of each solar cycle as the sun’s inner magnetic dynamo re-organizes itself. The coming reversal will mark the midpoint of Solar Cycle 24. Half of ‘Solar Max’ will be behind us, with half yet to come.
Hoeksema is the director of Stanford’s Wilcox Solar Observatory, one of the few observatories in the world that monitor the sun’s polar magnetic fields. The poles are a herald of change. Just as Earth scientists watch our planet’s polar regions for signs of climate change, solar physicists do the same thing for the sun. Magnetograms at Wilcox have been tracking the sun’s polar magnetism since 1976, and they have recorded three grand reversals—with a fourth in the offing.
Astronomers at the Wilcox Solar Observatory (WSO) monitor the sun’s global magnetic field on a daily basis. WSO home page
Solar physicist Phil Scherrer, also at Stanford, describes what happens: “The sun’s polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity. This is a regular part of the solar cycle.”
A reversal of the sun’s magnetic field is, literally, a big event. The domain of the sun’s magnetic influence (also known as the “heliosphere”) extends billions of kilometers beyond Pluto. Changes to the field’s polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space.
When solar physicists talk about solar field reversals, their conversation often centers on the “current sheet.” The current sheet is a sprawling surface jutting outward from the sun’s equator where the sun’s slowly-rotating magnetic field induces an electrical current. The current itself is small, only one ten-billionth of an amp per square meter (0.0000000001 amps/m2), but there’s a lot of it: the amperage flows through a region 10,000 km thick and billions of kilometers wide. Electrically speaking, the entire heliosphere is organized around this enormous sheet.
During field reversals, the current sheet becomes very wavy. Scherrer likens the undulations to the seams on a baseball. As Earth orbits the sun, we dip in and out of the current sheet. Transitions from one side to another can stir up stormy space weather around our planet.
An artist’s concept of the heliospheric current sheet, which becomes more wavy when the sun’s magnetic field flips. More
Cosmic rays are also affected. These are high-energy particles accelerated to nearly light speed by supernova explosions and other violent events in the galaxy. Cosmic rays are a danger to astronauts and space probes, and some researchers say they might affect the cloudiness and climate of Earth. The current sheet acts as a barrier to cosmic rays, deflecting them as they attempt to penetrate the inner solar system. A wavy, crinkly sheet acts as a better shield against these energetic particles from deep space.
As the field reversal approaches, data from Wilcox show that the sun’s two hemispheres are out of synch.
“The sun’s north pole has already changed sign, while the south pole is racing to catch up,” says Scherrer. “Soon, however, both poles will be reversed, and the second half of Solar Max will be underway.”
When that happens, Hoeksema and Scherrer will share the news with their colleagues and the public.
Source: NASA press release, h/t to Dr. Leif Svalgaard
VIDEO:
Related articles
- The solar cycle is still slumping (wattsupwiththat.com)
- Sun’s 2013 Solar Activity Peak Is Weakest in 100 Years (space.com)
James At 48 says:
August 6, 2013 at 2:54 pm
So we have probably hit the max for the current cycle.
In a sense, yes, but weak cycles do not have a sharp, well-defined maximum, so we’ll be in a ‘maximum state’ for several years.
Leif,
My passion has mostly been the connection between solar inertial motion and axial precession.
Has the connection between HCS and the lunar cycle been exhausted. (since this wave overtakes the earth 13 to 14 times a year)
Now then, current sheet is made of ‘things’ (electrons and protons with the associated magnetic field), these are individual parts of the current sheet, and all travel in a strait lines away from the source, or to put it another way, any individual section of the structure moves out radially, but the structure rotates.
Now it is all clear to everyone, no room for misinterpretation. Thanks.
TLMango says:
August 6, 2013 at 3:14 pm
Has the connection between HCS and the lunar cycle been exhausted. (since this wave overtakes the earth 13 to 14 times a year)
The HCS stretches throughout the entire solar system and can be computed from the observed magnetic field on the Sun, so it is very doubtful [impossible] that our tiny moon has any influence on the HCS.
vukcevic says:
August 6, 2013 at 3:16 pm
Now it is all clear to everyone, no room for misinterpretation.
It is good to see that you have no further misinterpretations.
Leif,
I’m sorry. I meant to say, is the possibility of HCS influencing lunar cycle been looked at exhaustively. I didn’t suggest our tiny moon was influencing HCS.
TLMango says:
August 6, 2013 at 3:51 pm
I’m sorry. I meant to say, is the possibility of HCS influencing lunar cycle been looked at exhaustively. I didn’t suggest our tiny moon was influencing HCS.
We measure constantly the distance to the Moon with millimeter accuracy and the variations are accounted for so there does not seem to be any extraneous influence. I wouldn’t expect any because the density of particles carrying the current is so incredible low [10 particles per cc].
Leif Svalgaard quoted and responded:
“Now it is all clear to everyone, no room for misinterpretation.
It is good to see that you have no further misinterpretations.”
Is that a peace agreement or an armistice? 😉
I ask because I’m still struck (stuck?) by the notion of electrons and protons having their vectors altered by magnetic fields. So since the Sun’s magnetic field rotates with it, will the charged particles be deflected from a radial path?
PJF says:
August 6, 2013 at 4:42 pm
Is that a peace agreement or an armistice?
Vuk is apt to misinterpret things, so now and then he must be brought back onto the straight and narrow road.
So since the Sun’s magnetic field rotates with it, will the charged particles be deflected from a radial path?
No [well a tiny, tiny bit which is of no consequence]. Look at slide 8 of http://www.leif.org/research/On-Becoming-a-Scientist.pdf From the Sun at the lower right you’ll see an arrow stretching radially away from the Sun. Look at the particle labeled ‘6’. It was ejected from the Sun 5 days ago. Yesterday it was at point 5, day before that at 4, day before that at 3, then at 2 and at 1. The point on the Sun that was in position 1 five days ago has in the meantime rotated to the point on the Sun marked 6. So when a particle is at point 6 on the arrow, the point on the Sun where it came from has rotated to point 6 on the edge of the Sun. Since the magnetic field is ‘frozen’ into the plasma [this means that the field and the plasma move together], the magnetic field line that pervades point 6 on the arrow came from point 6 on the Sun. At days 2, 3, 4, etc, point 6 were on the arrows drawn to the left [originating from points 1, 2, 3, etc on the Sun. You can see that all the points marked 6 lie on a spiral although the movements are always straight away from the Sun. Think of the drops from a rotating lawn sprinkler, they do the same.
Soon, the doomsayers will come with all sorts of new theories on how this will end the world somehow. Yup, it is an 11 year cycle, but I have little faith in people and I’m sure most of these kinds of fools will overlook that fact.
Thanks for your reply, Dr S. In the meantime I’d read the Wikipedia page for the heliospheric current sheet, and your explanation helped me understand their explanation (of the radial motion). I can see how any charged particles won’t be deflected by the part of the magnetic field they carry with them (are frozen with), but presumably faster moving particles (from CMEs, etc) will encounter the twisted spiral and be deflected from a radial path. Certainly something is deflecting the outbursts seen in this LASCO animation:
http://en.wikipedia.org/wiki/File:LASCO20011001.gif
Looking inward rather than outward, does the solar core have any effect on the magnetic field and other outer layer action (other than providing the energy for it)? In other words, is there any “information” coming from the core that causes any changes? And does the magnetic field alter activity in the core?
Thanks again for your output. You must feel quite a bow shock against the density out here.
rgds
Peter
[i]Look at it as [free] education. [/i]
I don’t. I look at it some acolytes of the bow shock theory scrambling to bash their theory to fit the latest fact. It’s pretty standard procedure that new space data doesn’t fit theory.
Let me summarize: A year ago, it was found that the solar wind moved a tad slower than thought.
That’s the most obtuse and dismissive interpretation of the v1 data I’ve heard. It doesn’t acknowledge the unexpected sudden drop to nera zero of >0.5MeV solar wind particles.
Why would a leader of the v1 team say ” “All theoretical models have been found wanting.” if theory and data where out by only a “tad” ?
Using the models then available McCormack and colleagues computed by simulation that the models predicted no bow shock. A year later, using improved models, the same authors found that a bow shock was likely to form.
That’s leif speak for computer modeller bashing there models post hoc to fit new data and predict what they want to be predicted.
It does, just like the Earth’s magnetic field is an obstacle for the solar wind to collide with.
Well say solar system’s magnetic field , rather than solar system.
And anyway it doesn’t explain the cessation of the solar wind.
When there is a pressure balance between the solar wind and the interstellar medium, the solar wind stops.
If its got such a simple rational then why wasn’t it predicted? Why were ” All theoretical models … been found wanting ” ?
Isn’t the solar wind rather sparse out at 230AU? How come nearly all solar wind particles lose all their velocity in the same small region of the outer solar system. If the solar wind was up against an interstellar wind, then the disruption of particle trajectories by collision should be a smoothly increasing incidence with distance.
PJF says:
August 6, 2013 at 6:46 pm
Looking inward rather than outward, does the solar core have any effect on the magnetic field and other outer layer action (other than providing the energy for it)? In other words, is there any “information” coming from the core that causes any changes? And does the magnetic field alter activity in the core?
Now and then the idea of a ‘relic’ magnetic field billions of years old residing in the core crops up. This idea is not generally accepted and we don’t know of any observable effect that can be ascribed to that relic field.
The sunspots do not interfere with the core.
meemoe_uk says:
August 6, 2013 at 7:00 pm
That’s leif speak for computer modeller bashing there models post hoc to fit new data and predict what they want to be predicted.
That is McCormack acknowledging that he was wrong a year ago when he said there was no bow shock.
If its got such a simple rational then why wasn’t it predicted? Why were ” All theoretical models … been found wanting ” ?
It was predicted 50 years ago.
If the solar wind was up against an interstellar wind, then the disruption of particle trajectories by collision should be a smoothly increasing incidence with distance.
The particles never collide out there. The magnetic field is what makes the solar system stiff.
Your education continues.
Leif Svalgaard says:
August 6, 2013 at 7:15 pm
That is McCormack acknowledging that he was wrong a year ago when he said there was no bow shock.
I should spell his name correctly: McComas
To remind you of his paper:
“Current estimates of plasma parameters in the local interstellar medium indicate that the speed of the interstellar wind, i.e., the relative speed of the local interstellar cloud with respect to the Sun, is most likely less than both the fast magnetosonic speed (subfast) and the Alfvén speed (sub-Alfvénic) but greater than the slow magnetosonic speed (superslow). In this peculiar parameter regime, MHD theory postulates a slow magnetosonic shock ahead of the heliosphere, provided that the angle between the interstellar magnetic field and the interstellar plasma flow velocity is quite small (e.g., 15° to 30°). In this likely scenario, our multifluid MHD model of the heliospheric interface self-consistently produces a spatially confined quasi-parallel slow bow shock. Voyager 1 is heading toward the slow bow shock, while Voyager 2 is not, which means that the two spacecraft are expected to encounter different interstellar plasma populations beyond the heliopause. The slow bow shock also affects the density and spatial extent of the neutral hydrogen wall.”
This is now. What you are stuck on was then.
meemoe_uk says:
August 6, 2013 at 7:00 pm
That’s leif speak for computer modeller bashing there models post hoc to fit new data and predict what they want to be predicted.
You may take this to heart: http://www.leif.org/EOS/2013-07-voyager-solar.pdf
“In space, a bow shock is similar to the shockwave formed ahead of the wing of a plane or the bow of a moving ship. They are often formed when a solar wind encounters a planet’s magnetic field. Earth has a thin bow shock formed approximately 90,000 km ahead of the planet. Just as planets move throughout the solar system, the system itself is moving through the Milky Way. As it travels, the Sun’s magnetic field interacts with the interstellar magnetic field and the mix of dust and gas that permeates deep space. Scientists believe the bow shock builds ahead of the leading edge of the solar system as it travels through the cosmos and the gas, dust, and cosmic rays of the interstellar medium slow down and pile up. While NASA research seemed to refute its existence, new research in Geophysical Research Letters found that the bow shock likely exists after all. The authors claim the solar system’s bow shock would be different to Earth’s, describing it as a “slow bow shock.”
B. Zieger and M. Opher, N. A. Schwadron, D. J. McComas, G. Tóth, “A slow bow shock ahead of the heliosphere”, Geophysical Research Letters, DOI: 10.1002/grl.50576, 2013.
Your education continues.
Thanks Dr. S. for bringing this to WUWT, “The sun is about to have a flipping magnetic field reversal.”
Good update, good review and good explanations for the newbies of the processes they are now hearing about. Help’s some of us solidify some basic information.
differential rotation and depolarization. Is depolarization based on rotation speeds?
Ya know maybe, solar max cycle 23 had a faster? bowshock as anticipated and this cycle 24 has a slower bowshock. Just goes with a weaker cycle?
Carla says:
August 6, 2013 at 8:16 pm
differential rotation and depolarization. Is depolarization based on rotation speeds?
not sure what you mean, but if mean polar field reversal, the short answer is ‘no’.
Ya know maybe, solar max cycle 23 had a faster? bowshock as anticipated and this cycle 24 has a slower bowshock. Just goes with a weaker cycle?
Larger cycles puff up the heliosphere, if that what you are after.
Leif Svalgaard – The compass would, indeed point to other way [on the Sun, not the Earth].
Thanks for answering my question.
Leif Svalgaard says:
August 6, 2013 at 8:27 pm
Carla says:
August 6, 2013 at 8:16 pm
differential rotation and depolarization. Is depolarization based on rotation speeds?
not sure what you mean, but if mean polar field reversal, the short answer is ‘no’.
—
If our sun is a good example of differential rotation, and differential rotation can create depolarization how is does that work?
One of my recent articles was stating that since cycle 10 there has been slowing in the equatorial region of the sun. And differential rotation does fluctuate from cycle to cycle and is even slower during a cycle like 24 as compared to 23.
In galaxies differential rotation creates “depolarization canals.” At regular intervals. Does the sun have a depolarization canal?
“We found a twisted magnetic flux rope, well
aligned with the polarity inversion line and a part of an Halpha
filament, and located where a large flare is initiated about two
hours later.”
What is the polarity inversion line?
Any chance of larger than usual solar flares hitting the earth from September thru December?
Leif Svalgaard says:
August 6, 2013 at 12:13 pm
The magnetic field at the poles is the stuff of which sunspot are formed inside the sun.
The polar fields are dragged into the Sun by circulation of material. At depth the magnetic field is amplified by induction. The resulting stronger fields float to the surface and there assemble into sunspots. Sunspots decay and the magnetic debris is carried to the poles and the process repeats. So there is a mixture of global and of small-scale processes.
—————-
What exactly is this “stuff”, the constituent parts that make up this “magnetic debris”? I presume it is composed of masses of charged plasma particles that have a magnetic field induced by kinetic motion and or electric current. Are there aggregations of heavier nuclei behaving analogous to a lava lamp?
Leif Svalgaard says:
Vuk is apt to misinterpret things, so now and then he must be brought back onto the straight and narrow road.
How true. However, Vuk knew perfectly well how the HCS is organised and its properties, but this being an interesting concept , he asked the question some of the readers may be puzzled by but reluctant to ask.
Introducing practical concept of the rotating magnetic fields:
Unrelated and not analogues to HCS, 139 years ago, one of the greatest and most beneficial discoveries for the humanity was made by Nikola Tesla. Physics and mathematics of rotating magnetic field (see animation in the link below) was pursued to a great detail at my university some decades ago.
http://en.wikipedia.org/wiki/Rotating_magnetic_field
that was 130 years ago (1882)
Owen in GA says:
August 5, 2013 at 8:23 pm
still frozen…Part of the reason for the ice free caps millions of years ago was the continental configuration. With North and South America separated by a shallow sea rather than the isthmus of Panama, there is thought that the ocean circulation patterns mixed the waters differently…..
>>>>>>>>>>>>>>>
There was also Drakes Passage.
Drake Passage and palaeoclimate
Reseach on Drakes Passage today: http://climate.gmu.edu/research/drake.php