Solar Science

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Archive for August 2009

Failed Predictions of Solar Cycle 24 – #1 Dikpati and Hathaway 2006

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Looking back into the archives, there are many many predictions of the start and size of solar cycle 24 given on the highest possible scientific authority that turned out to be flat out wrong.

Here’s one

March 10, 2006: It’s official: Solar minimum has arrived. Sunspots have all but vanished. Solar flares are nonexistent. The sun is utterly quiet.

Like the quiet before a storm.

This week researchers announced that a storm is coming–the most intense solar maximum in fifty years. The prediction comes from a team led by Mausumi Dikpati of the National Center for Atmospheric Research (NCAR). “The next sunspot cycle will be 30% to 50% stronger than the previous one,” she says. If correct, the years ahead could produce a burst of solar activity second only to the historic Solar Max of 1958.

This is important. The solar minimum began around March 2006 and today August 30, 2009 the Sun is still in that minimum with no sign of it ending.

The failed predictor: The Solar Conveyor Belt Theory


Dikpati’s prediction is unprecedented. In nearly-two centuries since the 11-year sunspot cycle was discovered, scientists have struggled to predict the size of future maxima—and failed. Solar maxima can be intense, as in 1958, or barely detectable, as in 1805, obeying no obvious pattern.

The key to the mystery, Dikpati realized years ago, is a conveyor belt on the sun.

I try to remove some of the waffle here because the article talks about the Earth’s ocean conveyor belt as an analogue but frankly its not relevant, nor useful.

The sun’s conveyor belt is a current, not of water, but of electrically-conducting gas. It flows in a loop from the sun’s equator to the poles and back again. Just as the Great Ocean Conveyor Belt controls weather on Earth, this solar conveyor belt controls weather on the sun. Specifically, it controls the sunspot cycle.

Solar physicist David Hathaway of the National Space Science & Technology Center (NSSTC) explains: “First, remember what sunspots are–tangled knots of magnetism generated by the sun’s inner dynamo. A typical sunspot exists for just a few weeks. Then it decays, leaving behind a ‘corpse’ of weak magnetic fields.”

Enter the conveyor belt.

The Solar Conveyor belt according to NASA

The Solar Conveyor belt according to NASA

“The top of the conveyor belt skims the surface of the sun, sweeping up the magnetic fields of old, dead sunspots. The ‘corpses’ are dragged down at the poles to a depth of 200,000 km where the sun’s magnetic dynamo can amplify them. Once the corpses (magnetic knots) are reincarnated (amplified), they become buoyant and float back to the surface.” Presto—new sunspots!

Presto! No, it didn’t this time. This time the belt moved to the critical latitude of 22 degrees and we got a single sunspot and that’s it.

All this happens with massive slowness. “It takes about 40 years for the belt to complete one loop,” says Hathaway. The speed varies “anywhere from a 50-year pace (slow) to a 30-year pace (fast).”

When the belt is turning “fast,” it means that lots of magnetic fields are being swept up, and that a future sunspot cycle is going to be intense. This is a basis for forecasting: “The belt was turning fast in 1986-1996,” says Hathaway. “Old magnetic fields swept up then should re-appear as big sunspots in 2010-2011.”

There’s the prediction from 2006. We’ve yet to reach 2010 but Hathaway was talking about 2010-2011 as the time of the SC24 maximum when we haven’t yet reached the end of the minimum in August 2009.

Here’s where the claim of scientific authority is made. This isn’t just any old joe making a prediction, this is expertise:

Like most experts in the field, Hathaway has confidence in the conveyor belt model and agrees with Dikpati that the next solar maximum should be a doozy. But he disagrees with one point. Dikpati’s forecast puts Solar Max at 2012. Hathaway believes it will arrive sooner, in 2010 or 2011.

“History shows that big sunspot cycles ‘ramp up’ faster than small ones,” he says. “I expect to see the first sunspots of the next cycle appear in late 2006 or 2007—and Solar Max to be underway by 2010 or 2011.”

Wrong. An expert strikes out.

Who’s right? Time will tell. Either way, a storm is coming.

It turns out that neither was right. The extended solar minimum caught some of NASA’s brightest experts with their predictive pants down.

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Written by John A

August 29, 2009 at 1:28 pm

Testing the "Watts Effect"

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On Anthony Watts’ blog, he’s testing his apparent paranormal power to cause the Sun to break out into sunspots by writing about how blank the Sun is.

On this blog, I don’t believe in the paranormal, and it looks like the Sun is still slumbering, with no end in sight.

Here is the stereo view looking behind the Sun to the surface that has yet to come into view:

Stereo image of solar farside 29-08-2009

Stereo image of solar farside 29-08-2009

Nothing to report other than a coronal hole. Looks like Anthony’s got no more powers than I have.

Here’s the solar cycle progression to July 2009.

ISES Solar Cycle Progression Jul 2009

ISES Solar Cycle Progression Jul 2009

With August 2009 expected to be zero, that red line prediction is looking more and more optimistic.

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Written by John A

August 28, 2009 at 7:20 pm

Posted in Solar Cycle 24

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SOHO back online: Sun still blank

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It’s difficult sometimes to carry on a blog when the primary focus of your discussion doesn’t do anything. That’s the nature of solar minima, I guess, but particularly true when you have an apparent regime change in the solar cycle.

The latest news is that SOHO is back online after a glitch forced the software onboard to be reloaded with new commands, and mission controllers took an opportunity to bake all of the CCDs onboard the spacecraft to remove dead pixels.

Today the Sun is blank.

EIT195-23-8-2009

This image from the EIT (Extreme ultra-violet Imaging Telescope) at 195 Angstroms show no spots and no significant coronal holes.

Written by John A

August 22, 2009 at 2:30 pm

S. Fred Singer and Terry Sloan correspond on CR deflection

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S. Fred Singer corresponds on the subject:

Some corrections to the letter from Terry Sloan:

1.  First, a minor point:  The solar particle stream (“wind”) does not ‘generate’ a mag field.  A somewhat turbulent solar surface field is ‘frozen in ‘ (a la Alfven) into the stream and decays only slowly

2.  The ‘deflection’ argument may be intuitive but doesn’t really work logically.  For every CR particle aimed at the Earth that’s deflected away, there will be one not aimed at the Earth that’s deflected to hit the Earth

3.  The 11-yr cycle seen in CR intensity (and other solar-modulated CR variations)  depend on deceleration (i e, a shift in the energy  spectrum) produced by scattering of CR from expanding regions of magnetic turbulence.  I have termed this mechanism an ‘inverse Fermi acceleration.’  The decrease in CR intensity then follows directly from an application of Liouville’s theorem.

S.F. Singer, “Cosmic Ray Time Variations Produced by Deceleration in Interplanetary Space.” Nuovo Cimento 8, Suppl. II, 334 – 341, 1958.  Laster, H., A.M. Lenchek and S.F. Singer. “Interplanetary Gas Cloud Modulation of Cosmic Rays.” Bull. Am. Phys. Soc., 5, 259, 1960:  J. Phys. Soc. Japan, 17, Suppl. AII, 583, 1962

I am not aware of any direct measurement of this shift in the primary CR energy spectrum but a comparison of CR neutron monitor data  with those of mu-mesons does suggest confirmation.

Best

Fred

and Terry Sloan responds:

Dear Fred,

Thank you for your e mail. I interleave some comments.

Regards, Terry.

Dear Benny

Some corrections to the letter from Terry Sloan:

1. First, a minor point: The solar particle stream (“wind”) does not ‘generate’ a mag field. A somewhat turbulent solar surface field is ‘frozen in ‘ (a la Alfven) into the stream and decays only slowly

—–> I agree that it is more complicated than my simple heuristic explanation.

2. The ‘deflection’ argument may be intuitive but doesn’t really work logically. For every CR particle aimed at the Earth that’s deflected away, there will be one not aimed at the Earth that’s deflected to hit the Earth

——> I agree with this point for very high energy CR but at low energy, where the deflections are larger, particles undergo sling shot effects and more are lost than are gained. Hence the influence of solar activity.

3. The 11-yr cycle seen in CR intensity (and other solar-modulated CR variations) depend on deceleration (i e, a shift in the energy spectrum) produced by scattering of CR from expanding regions of magnetic turbulence. I have termed this mechanism an ‘inverse Fermi acceleration.’ The decrease in CR intensity then follows directly from an application of Liouville’s theorem.

—-> Again I agree that it is more complicated than my simple argument. However, I do not like this argument since the particles themselves are not decelerated. However, I agree that there is a shift in the spectrum.

S.F. Singer, “Cosmic Ray Time Variations Produced by Deceleration in Interplanetary Space.” Nuovo Cimento 8, Suppl. II, 334 – 341, 1958. Laster, H., A.M. Lenchek and S.F. Singer. “Interplanetary Gas Cloud Modulation of Cosmic Rays.” Bull. Am. Phys. Soc., 5, 259, 1960: J. Phys. Soc. Japan, 17, Suppl. AII, 583, 1962

I am not aware of any direct measurement of this shift in the primary CR energy spectrum but a comparison of CR neutron monitor data with those of mu-mesons does suggest confirmation.

—-> There is another greater effect on muons which is the energy threshold when the CR interact in the atmosphere. Pion multiplicities grow with energy. So muons tend to be produced by much more energetic CRs than those which produce the majority of the neutron monitor counts. Hence they are less susceptible to variations in the solar activity.

I’m not quite convinced with Fred’s statement that the position is neutral for cosmic ray deflection in the case that the protons have the same energy as the solar wind or less, but I’ll have to do more calculations on that point.

Update: S. Fred Singer replies

Terry

You may be right about the last point (the muons).

It would help if someone could measure the shift in energy spectrum over the solar cycle — or during Forbush decreases.

Just the latitude variation of total counts, measured from a satellite.

Can you get such data?

Best

Fred

Written by John A

August 17, 2009 at 2:04 pm

Posted in Svensmark

Terry Sloan replies on the Svensmark process

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Terry Sloan has written his thoughts on my calculations as to whether Svensmark’s process should cause sufficient deflection towards the Earth’s magnetic poles to be measureable:

The word ‘funnelling’ is very misleading. I do not know where it  came from – it was not from me. Forget it – here is the real story.

Cosmic rays from outside the solar system come with a very wide spectrum of energies from zero up 10^20 eV. The intensity falls off  very rapidly as the energy increases (roughly proportional to E^-2.7, i.e. one over E to 2.7 th power, where E is energy). At low energies they are mainly protons with about 20% Helium and then smaller amounts of heavier nuclei.

The sun pours pours out streams of charged particles as well and this is called the solar wind. These are usually at low energies (much below 10^9 eV). These streams of particles form electric currents which generate a magnetic field. This field is still finite out to very  large distances (up to 100 times the distance from sun to Earth – this is 100 AU, 1 AU=astronomical unit = sun Earth distance)

Imagine a cosmic ray coming from outside the solar system in the direction of the Earth. If the ray has very high energy it is hardly deflected and so can hit the Earth.

However, at lower energies it feels  a finite deflection and it does not need much of a deflection at a large distance from the Earth to miss the Earth.

Now the solar wind is stronger at the peak of the sun spot number in its 11 year cycle than at the minimum activity. Hence less of the lower  energy cosmic rays hit the Earth during solar maximum.

Have a look at a cosmic ray monitor (see http://ulysses.sr.unh.edu/NeutronMonitor/Misc/neutron2.html and follow the links on there). You can clearly see the 11 year solar cycle on the cosmic ray rate. The rate varies by 15-20% from solar max to solar min.

The cosmic ray has not yet finished. If it manages to evade the magnetic field generated by the solar wind it then has to get through the Earth’s magnetic field. Near the Earth’s equator this field tends to be about perpendicular to a particle hitting the Earth. So again low energy particles are deflected away and do not hit the Earth.

Near the poles a cosmic ray aiming at the Earth travels parallel to these field lines which then have very little effect (remember that the force on a charged particle moving in a magnetic field is perpendicular to the velocity and the field).

Hence you see less 11 year modulation on the cosmic ray rate near the equator but a larger effect near the poles. Have a look at the Climax (somewhere near the pole) and Huancayo (close to the Equator) monitors (do a Google on them) and you will see what I mean.

I hope this helps.

Regards,

Terry Sloan.

Here are plots of Climax and Huancayo that Terry was referring to:

Written by John A

August 17, 2009 at 1:55 pm

Posted in Svensmark

Offline: We've gone temporarily blind

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The SOHO instruments are offline while new software commands are uploaded. As the main instruments are offline, the other CCD systems are being baked out (heated up to clear dead pixels)

From Spaceweather.com

Solar and Heliospheric Observatory (SOHO) is having a minor problem. SOHO’s white light solar telescope is temporarily offline while new commands and data tables are uploaded to the spacecraft. Normal operations are expected to resume in a few days.

Hence no updates on the state of the Sun.

The Sun could have a sudden burst of activity and we’d never know.

Written by John A

August 7, 2009 at 11:02 am

Posted in News and Views

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