I initially wrote this article using data only from David Archibald, but within a couple of minutes I was given some broader data from Leif Svalgaard, so I have rewritten this to include both resources in the interest of seeing the broader perspective. – Anthony
Last September WUWT covered NASA’s press conference on the state of the sun. One of the announcements was this:
Sept. 23, 2008: In a briefing today at NASA headquarters, solar physicists announced that the solar wind is losing power.
“The average pressure of the solar wind has dropped more than 20% since the mid-1990s,” says Dave McComas of the Southwest Research Institute in San Antonio, Texas. “This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.”
From Wiki:
The solar wind is a stream of charged particles—a plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 keV. The stream of particles varies in temperature and speed with the passage of time. These particles are able to escape the sun’s gravity, in part because of the high temperature of the corona, but also because of high kinetic energy that particles gain through a process that is not well-understood.
The solar wind creates the Heliosphere, a vast bubble in the interstellar medium surrounding the solar system. Other phenomena include geomagnetic storms that can knock out power grids on Earth, the aurorae such as the Northern Lights, and the plasma tails of comets that always point away from the sun.The solar wind is a stream of charged particles—a plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 keV. The stream of particles varies in temperature and speed with the passage of time. These particles are able to escape the sun’s gravity, in part because of the high temperature of the corona, but also because of high kinetic energy that particles gain through a process that is not well-understood.
The solar wind creates the Heliosphere, a vast bubble in the interstellar medium surrounding the solar system. Other phenomena include geomagnetic storms that can knock out power grids on Earth, the aurorae such as the Northern Lights, and the plasma tails of comets that always point away from the sun.
Solar Wind Flow Pressure is something that is tracked daily by the Space Weather Prediction Center (SWPC) For example they display a nifty solar wind dashboard gauge on Space Weather Now that shows “dynamic pressure”:
Dynamic Pressure Dial:
Ranges from 0.1 to 100 nPa. The scale is log10 over the full range. If the density or speed data are missing, the arrow will not appear. The arrow will move to the location on the scale corresponding to the actual value of the latest 15 minute average of the Dynamic Pressure P of the solar wind. Dynamic Pressure is a function of speed and density.
David Archibald writes:
Robert Bateman’s graphic of the solar wind sent me in search of a longer time series. I found a longer one, and one that is a more accurate indication of the force that is pushing the galactic cosmic rays out from the inner planets of the solar system. It is the three month smoothed, 27 day average of the solar wind flow pressure. The data is from the Omniweb site.
The narrow downtrend channel that started in 2005 is quite evident. Before that it was trendless, and didn’t change with solar cycle amplitude. The volatility within the downtrend is much less than it was prior to 2005. Also evident is a big oscillation in 2004, which may be an artefact of a switch that changed the mode.
From this chart, solar activity is still falling until the downtrend channel is broken. As the solar wind takes a year to reach the heliopause, the Oulu neutron count will continue to rise for the next year. But just as the Earth’s atmosphere has shrunk, the heliopause will also be shrinking.
However this Archibald graph only shows a narrow slice of the entire data picture, Leif Svalgaard has an OMNI2 dataset that tracks back to 1963:
While we can indeed see the current downtrend since 1997, we have had periods before where the solar wind has been almost as low . Though NASA said last year “This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.”.
There is an overall down trend since 1992, with a short plateau at the last solar max around year 2000-2004, followed by another downtrend starting about 2005.
In terms on the sun’s history (if it were compared to a day) we have about a microsecond worth of data out of that day on display above. So what conclusion, if any, can we draw from it? The only one I can see is it showing reduced solar activity, but nothing profound (in terms of the solar wind data we have) except that. We see a low period of similar amplitude around 1970, but it is noisier. The trend we’ve seen since 2005 is less noisy, which is inline with the quiet sun we have observed recently.
Let’s hope sol gets the magneto revved up again.
UPDATE: I had written to David Archibald, saying that “the broader data set to 1963 didn’t agree with your conclusions”, and he wrote back within about 15 minutes and provided a new graph:
Anthony, Agreed, and thankyou.
I went back to find the larger data set, as follows:
It is evident that the longer picture is more complicated. The correlation with solar minima and maxima is quite poor. Activity did not recover into Solar Cycle 23.
Yours sincerely,
David Archibald
So now we have all the makings of a good debate.
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And we should be scientific about that, idflex, and start keeping record worldwide of rock temperature.
But if you are considering journeying below 13,000 ft into rock, try taking a trip to the Witwaterrand Mine in S. Africa. I doubt you would last more than a minute beyond the air conditioner. It’s 135F down there in the depths.
rbateman (20:13:10) :
try taking a trip to the Witwaterrand Mine in S. Africa.
While in Africa go visit the Oklo natural nuclear reactor site:
http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml
Lief: I can see that V^2 was lowest in 1901, and so was B, so I would go with 1901 as being the low point.
What is our current value of B ?
Leif Svalgaard (16:21:35) :
vukcevic (15:37:03) :
As I said, no amount of sound science and meaningful arguments would have any effect on a true ‘believer’……..By that ‘logic’, there is a 50% chance that I win the lottery tomorrow.
Interesting link, confirms that charging is (where +Q = – Q) is function of the velocity differential. Case mentioned is somewhat different, spacecrafts in the Earth’s orbit (within magnetosphere, Van Allen belt etc) to the Ulysses’ orbit electrostatic properties, including absence of ‘night time’. Its spin rate is generally constant at approximately 5 rpm so any (non compensated) charge build up on the dark side should be minimal considering low density at Ulysses 1.5 – 5AU (<and << 7e/cm3) for darks side lasts only 6sec. http://ulysses-ops.jpl.nasa.gov/ulysses/ftp/CDROMS/ULS_04_A/HTML/ORBIT1.GIF
In this case of solar wind any volume at any time may be neutral (Q1 = Q2 =Q) but that does not prevent excess current flow due to velocity differential:
I1= nSv1Q , I2= nSv2Q, resultant current I=I1-I2 = nSQ(v1-v2).
Since the electron flux appear to be greater (moving away from the Sun), then current flow is into the Sun.
Also the results shown in FIGURE 1. could be of interest (in view of velocity differential)
http://ulysses-ops.jpl.esa.int/ulysses/ftp/CDROMS/ULS_01_A/Docs/SWOOPS/SWOOPS.HTM
re probability: p=k/n (ratio of favourable and total outcomes); 2 instruments vs. millions of lottery players, not exactly comparable. The statement thus fractionally reduces probability of your previous qualification being correct.
Correction: Ignore spin rate (it appears to be around axis directed at Sun).
Leif Svalgaard: Natural reactors have been found [near the surface]. U and Th, although heavy, fit into the crystal structure of minerals that are found in the crust and are therefore not found in the core. So, not much to expect from that corner.
So where’s all that heat being generated inside the Earth? The crust rather than the core?
rbateman: And we should be scientific about that, idflex, and start keeping record worldwide of rock temperature.
So every surface station should have an accompanying undersurface station?
And would we just measure temperature? Could we not also measure pressure? Use gps to measure ground speed? Is there an undersurface analogue of atmospheric humidity?
There’d be the same possibilities of heat island effects. If the air above NYC is several degrees higher than in sorrounding places, perhaps the earth beneath it is also several degrees higher too? How far down do you have to go to minimize the surface effects? Surface stations stand on legs a metre or two high. The undersurface stations might need ‘legs’ (pointing downwards) a kilometre long. And then we’s start thinking of hills and mountains as being transient clouds on the surface of the undersurface weather machine, in which everything happens very, very slowly.
In this manner we could scare the wits out of ourselves in entirely new ways.
Leif Svalgaard (16:47:21) :
The bottom line is that the solar cycle variation in one wavelength regions can be different [even opposite] to that in another region, and that that is not taken into account by the IPCC models.
Thanks Leif.
rbateman (22:35:12) :
What is our current value of B ?
For the last solar Bartels rotation that just ended yesterday B was 3.9 nT. Because we are now close to aphelion, the corrected to 1 AU value would be 4.1 nT . For the last six rotations B has been 4.1 nT, so it is pretty steady.
vukcevic (01:15:53) :
“Interesting link, confirms that” the plasma is neutral.
re probability: p=k/n of equally probable and independent events. A short course of probability would do you good.
Particle velocity distributions are highly anisotropic in the solar wind because of its low density. Here http://spc.igpp.ucla.edu/ssc/tutorial/solwind_magsphere_tutorial.pdf is a good tutorial on that. I cite from it [page9]: “A paradox is introduced by this difference in velocity that arises because in the corona the ions and electrons have similar temperatures but very dissimilar masses. In a collisionless gas, like the solar wind over most of its transit from the sun, charged particles do not leave their magnetic field lines. They also maintain quasi charge-neutrality. How can they do this if they are not traveling at the same speed? The answer is trivial if the source regions on the sun are constant in time so that the flux of electrons and ions at the base of a field line is constant. The density is always the same and it does not matter if the protons and ions stream relative to each other along the field. If the solar wind production rate varies in time and the ion density along a flux tube varies with distance, then the electrons have to slow down as they pass through dense regions and then speed up in rarefied regions. This occurs because when there is an over abundance of ions there will be a polarization electric field that attracts the electrons to that region. In regions of under dense ions the electrons will be expelled by the excess negative charge. As a result, charge imbalances are minimal in the solar wind despite the speed differences and time variations. We might expect variations in the electric potential along the magnetic field but no detectable variation in charge neutrality.”
idlex (02:42:51) :
So where’s all that heat being generated inside the Earth? The crust rather than the core?
Some, yes, but the most is coming from two sources: 1) the high pressure [when you compress things they get hot], and 2) left-over heat from the formation of the Earth.
Leif Svalgaard (06:40:59) :
Thanks for the link for the tutorial. I shall study it, and true to form look for little nuggets of controversy. I have to read your post carefully to avoid being told “H.G. is talking nonsense”. I think both of us understand probability sufficiently enough, so best left alone.
Thanks
How far down do you have to go to minimize the surface effects?
It is generally accepted in underground mining industry that 50 feet will do the trick. 100 feet if you want to be really picky.
I haven’t been in a mine yet that within 50 ft of the surface (horizontal or vertical) you were not confronted with the underground environment.
It could be 10 below or 110 above outside, and it won’t matter. You are at rock temperature.
vukcevic (10:17:31) :
I think both of us understand probability sufficiently enough, so best left alone.
Remember I pay back in same coin, so it is always up to you…
Leif Svalgaard (11:35:37) :
…….
Remember I pay back in same coin, so it is always up to you…
New one to me, I had to look it up in a phrase book, but any transgression I let go by my personal ‘magnetosphere’ at a speed of SW, with no reconnection, unless I find it personally attractive (e.g. ‘cyclomaniac’ or ‘man of superior ignorance’).
Back to the science; the tutorial on solar wind is very useful and sufficiently informative, but could do with more of up to date info. I am surprised that none of the articles on SW I have come across, have considered the electron’s wave property (lambda=h/mv, ignoring the relativistic part), but always purely as a particle. Have to look into that one. Anything you know of ?
vukcevic (13:15:35) :
Back to the science; the tutorial on solar wind is very useful and sufficiently informative, but could do with more of up to date info. I am surprised that none of the articles on SW I have come across, have considered the electron’s wave property (lambda=h/mv, ignoring the relativistic part), but always purely as a particle. Have to look into that one. Anything you know of ?
The fundamental physics does not depend on ‘up-to-date info’. The wave issue is not important or relevant. Nobody looks on purpose at things that are irrelevant. It is also hard to find SW articles discussing the amount of horse manure per cubic meter in the solar wind. The tutorial explains in plain language why the various velocity differences do not lead to charge imbalances or currents. The reason for the neutrality is basically that the electromagnetic forces are 10^39 times as strong as gravity so charges will short out unless the density is high enough that collisions prevents equalization. In solar wind and coronal plasmas the mean-free-path is enormous, so collisions play no role.
Leif Svalgaard: So where’s all that heat being generated inside the Earth? The crust rather than the core?
Some, yes, but the most is coming from two sources: 1) the high pressure [when you compress things they get hot], and 2) left-over heat from the formation of the Earth.
Do you not count radioactive decay of Th, U, and K as constituting a ‘nuclear reactor’ because it’s too dispersed? According to one source:
The present-day heat flow through the surface of the Earth is consistent with energy sources in the interior, including secular cooling, the gravitational contraction associated with cooling, and decline of radioactive abundances.
It estimates [Table 1b] the radiogenic component of global heat flow at 24-36 terawatts out of a total of 39-66 terawatts. i.e. about half. 39 terawatts works out at an average global surface heat flow of about 0.075 Watts/m^2. Most of the radiogenic heat is suggested to come from the lower mantle.
Leif Svalgaard (13:34:46) :
The fundamental physics does not depend on ‘up-to-date info’. The wave issue is not important or relevant. Nobody looks on purpose at things that are irrelevant. It is also hard to find SW articles discussing the amount of horse manure per cubic meter in the solar wind. ….. so charges will short out unless the density is high enough that collisions prevents equalization. In solar wind and coronal plasmas the mean-free-path is enormous, so collisions play no role.
‘Up to date info’ is a reference to latest data from Ulysses, Pioneer and Voyager. For the wave issue, it is not possible to say if it is relevant or not unless it is thoroughly researched.
Charges travelling from the same direction will not short or collide in presence of magnetic field (in vacuum space)! Hence, “In solar wind and coronal plasmas the mean-free-path is enormous, so collisions play no role”.
Tutorial does say “We might expect variations in the electric potential along the magnetic field but no detectable variation in charge neutrality.”
Electric potential difference in a conductive medium is a result of an electric current flow.
Definitely “no change in neutrality” nQ2 = – nQ1 but I1= SnQ1* v1 , I2= SnQ2 * v2, and I=I1+I2 = SnQ1*(v1-v2) electric current through cross section S due to the velocity difference so “We might expect variations in the electric potential along the magnetic field”.
I believe that “horse manure per cubic meter” is highly praised by market gardeners. Thank you again and Good night.
vukcevic (14:57:33) :
Leif Svalgaard (13:34:46) :
‘The fundamental physics does not depend on ‘up-to-date info’
Well, you have said your mind. I have tried to educate you on these things and I fail every time, so will not try [for a while] any longer as it evidently is quite hopeless. I can refer you to ‘Anaconda’ in another thread as an example of a similar [and equally hopeless] case: http://wattsupwiththat.com/2009/06/10/another-scientific-consensus-bites-the-dust/#comment-143706
idlex (14:41:18) :
Do you not count radioactive decay of Th, U, and K as constituting a ‘nuclear reactor’ because it’s too dispersed?
Precisely. I’ll prefer to use the words ‘nuclear reactor’ for a controlled chain reaction where the energy production is a coordinated process as different from the independent radioactive decays.
Leif Svalgaard: Precisely.
I see.
Then at what point would you concede that a fuzzy collection of decaying Th/U/K atoms around the centre of the Earth might be construed to be a ‘nuclear reactor’?
Perhaps the word ‘coordinated’ is the key. What happens when it isn’t coordinated, when it isn’t planned?
From what I know about uncoordinated, unplanned processes – like the orbit of the Earth around the Sun – there is always a cyclicity about them. The uncoordinated and unplanned Sun, as you well know (far better than I do) also has its cyclicities. Why should we suppose that the Earth beneath our feet is unchangingly regular?
I suspect that I may be pursuing a lost cause here, because the the 0.075 W/m^2 terrestrial surface heat loss from below pales into pallid insignificance beneath the majestic Sun above.
But I like pursuing lost causes.
idlex (18:58:28) :
Then at what point would you concede that a fuzzy collection of decaying Th/U/K atoms around the centre of the Earth might be construed to be a ‘nuclear reactor’?
Perhaps the word ‘coordinated’ is the key. What happens when it isn’t coordinated, when it isn’t planned?
This is not a question about conceding anything, but about education. The crucial point is that Th/U/K atoms by themselves decay spontaneously. A single U atom in empty space would all by itself some day decay. This is not what I would call a ‘reactor’. In a reactor, things are so arranged [either by us or by Nature] that the decay of one atom triggers the decay of other atoms [‘before its time’] which then trigger the decay of still other atoms, etc, so the decays are not independent [that is what I meant by ‘coordinated’]. This also happens in an atomic bomb [and we don’t really want that], so there are two more elements needed, namely a ‘moderator’ that will slow down the neutrons released to enhance the chain reaction and ‘control rods’ to stop or slow the reaction as we wish. In natural reactors, water plays the role of moderator and control rods are provided by the rock matrix in which the atoms are embedded. Such natural reactors are very rare and do not play any role in heating the Earth and, BTW, cannot any longer exist as the U235 needed for them to work has decayed so much that even chemically pure Uranium does not contain enough U235 for fission to work. So only billions of year ago could [and did] natural reactors exist here and there.
And finally, as you point out, the heat flow from the interior is totally insignificant.
Oh well. Yet another idea with which to become disenchanted! And it looked quite promising for a day or two.