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)
When the reversal happens, is there a period in which there is – for all practical purposes – NO magnetic field?
The GCR theory of cloud formation says that during quiet sun stages, a low magnitude solar magnetic field results in more clouds and cooler temperatures on Earth. Archibald and Hathaway suggests that the Earth will cool during the next few years because of this. If this is true, and there is a period of several months of weak-to-no solar magnetic field, should we not expect a coincident increase in global cloud cover (even if it is too short an interval to result in a temperature drop)?
We have satellite monitoring now, as well as the Earthshine project: I’d like to see a comparison of Earth’s albedo vs magnetic strength at the null points. If we have 3 peiods (including this upcoming one) we should see the impact, as the CERN experiment showed the impact of increased GCR to be both signficicant and immediate.
Interesting that the previous reversals have occurred at around ten years apart and this one looks close to 14 years. The strength of the previous magnetic fields is obvious in the graph, this maybe a better indicator of both cycle length and the effect on our climate.
Doug Proctor says:
August 5, 2013 at 5:15 pm
When the reversal happens, is there a period in which there is – for all practical purposes – NO magnetic field?
At a pole reversal the magnetic field goes away at that pole. There is plenty of magnetic field elsewhere on the Sun to make up for the disappearing polar fields. When the field at a pole disappears it is soon followed by a build up of field with the opposite polarity drifting up from lower latitudes.
” Just as Earth scientists watch our planet’s polar regions for signs of climate change”. What was the purpose of randomly including this sentence. I disrupted my interest in the subject, just as I have to turn off each and every nature show approximately 10 minutes before the end because they absolutely positively will say something about climate change.
to Leif Svalgaard, do field reversals happen in a similar manner for the earth, Iie. no total loss of field but a redistribution?
“Something big is abiut to happen on the sun” strikes me as a pretty bad overstatement, given that it happens every solar cycle. If it didn’t happen this time, well that would indeed be big.
“The sun’s north pole has already changed sign, while the south pole is racing to catch up,” says Scherrer”
Does that mean the Sun is a monopole?
wayne Job says:
August 5, 2013 at 5:21 pm
The strength of the previous magnetic fields is obvious in the graph, this maybe a better indicator of both cycle length
The polar fields at minimum are a good indicator of the strength of the next solar cycle. The cycle length is not the fundamental parameter, for example: cycle 4 was a very strong cycle [Peak sunspot number 141], but was 15 years long.
Pedantic old Fart says:
August 5, 2013 at 5:28 pm
do field reversals happen in a similar manner for the earth, Iie. no total loss of field but a redistribution?
No, the solar polar fields simply disappear but come back reversed. But this is only something that happens near the poles.
Bill Marsh says:
August 5, 2013 at 5:31 pm
Does that mean the Sun is a monopole?
No, as there is plenty of magnetic fields elsewhere on the Sun.
What is that line in the first chart saying “prediction made” referring to?
Dr. Svalgaard, the amplitude of the last few cycles appears to be decreasing, almost in a regular fashion. What is the explanation for this? Also, is there proxy or other evidence that would suggest that these changes in amplitude are part of some larger, regular cycle? thank you.
Can a peak in the Sun Spot Number occur after a flip?
righttimewrongplace says:
August 5, 2013 at 5:42 pm
What is that line in the first chart saying “prediction made” referring to?
The time at which we used the solar polar field strength to predict the size of the current cycle 24.
kevin Roche says:
August 5, 2013 at 5:43 pm
the amplitude of the last few cycles appears to be decreasing, almost in a regular fashion. What is the explanation for this? Also, is there proxy or other evidence that would suggest that these changes in amplitude are part of some larger, regular cycle?
There does seem to be a longer [100 years] ‘cycle’ in sunspot numbers http://sidc.be/sunspot-index-graphics/wolfaml.php It is not known why and the ‘cycle’ is likely just a temporary thing; it didn’t exist before 1700 and may not exist after 2013.
righttimewrongplace says:
August 5, 2013 at 5:43 pm
Can a peak in the Sun Spot Number occur after a flip?
Absolutely. See how many peaks there were in this cycle: http://www.solen.info/solar/cycl14.html
This is the stuff I love about this place.
Robert Wykoff at 5:25 pm “… just as I have to turn off each and every nature show approximately 10 minutes before the end because they absolutely positively will say something about climate change.”
On Vermont Public Radio it is a rare program or news byte that doesn’t lay the random ills of the earth on global-warming-climate-change. My seven year old picks up on it and, from the back seat, says “blah,blah,blah, right dad?”
“Half of solar max yet to come”? That’s what the video says. Does not sound accurate to me. Half of the solar cycle or the progression to solar minimum makes more sense. But then, I’m not a solar scientist. Leif?
Hopefully not too OT, but is this a fair description of the way the Solar System travels through intra-Galactic space?
http://www.djsadhu.com/the-helical-model-vortex-solar-system-animation/
And taking our Earth’s north pole as reference, is our Solar system heading in the north or south direction?
Sorry, this one…
The article does not mention the mention the pioneering work done by the JAXA team and the Hinode satellite where for the first time the north pole field reversal was observed, there is no instant process, complementary work.
This was observed spring 2012.
I would expect there to be great interest in any completion of reversal, if it is, given we saw the start.
I posted an article on this from where you can find links to the original material.
http://tallbloke.wordpress.com/2012/05/04/hinode-solar-magnetic-field-reversing-early-and-abnormally-implies-solar-maximum/
Other articles are around.
Thank you Dr. Svalgaard. I am sorry I did not ask my second question correctly. Is it common for a new cycle high in the smoothed SSN to occur after a flip or is it very likely we have seen the high for this cycle (twin peak or not.) Thanks!
Just as Earth scientists watch our planet’s polar regions for signs of climate change, solar physicists do the same thing for the sun.
Is it just me or did this poor excuse for a sentence make anyone else’s head explode?
It means we’re doomed, right?
Leif Svalgaard says:
August 5, 2013 at 5:49 pm
There does seem to be a longer [100 years] ‘cycle’ in sunspot numbers http://sidc.be/sunspot-index-graphics/wolfaml.php It is not known why and the ‘cycle’ is likely just a temporary thing; it didn’t exist before 1700 and may not exist after 2013.
===============================================
What is your basis for stating that it didn’t exist before 1700? OK, we have the Maunder minimum for the preceeding 50 years. But before that?
And what is your reason for supposing that it “may” not exist after 2013?
Bill_W says:
August 5, 2013 at 6:03 pm
But then, I’m not a solar scientist.
For a low cycle the ‘maximum’ is a long, drawn-out affair lasting several years with a polar field reversal halfway through…
tchannon says:
August 5, 2013 at 6:17 pm
The article does not mention the mention the pioneering work done by the JAXA team and the Hinode satellite where for the first time the north pole field reversal was observed
Because that work was not pioneering at all, just the Japanese not knowing the literature, see e.g. http://www.leif.org/research/Asymmetric-Solar-Polar-Field-Reversals-talk.pdf
August 5, 2013 at 6:20 pm
is it very likely we have seen the high for this cycle (twin peak or not.)
There will be more to come. The very notion of a ‘maximum’ becomes fuzzy and ill-defined for a cycle like SC24 and SC14.
StuartMcL says:
August 5, 2013 at 6:45 pm
What is your basis for stating that it didn’t exist before 1700? OK, we have the Maunder minimum for the preceeding 50 years. But before that?
We have about 10,000 years of cosmic ray proxies for solar activity and the ‘100-yr’ wave does not seem to exist in the earlier data.
And what is your reason for supposing that it “may” not exist after 2013?
I have reasons to believe that we may have another Maunder-type minimum, but that is speculation, of course, hence the may. You can see some of my reasons for this here: http://www.leif.org/research/SSN/Svalgaard12.pdf