From NASA JPL: Solar flares – they’re big and they’re fast. They can knock out a satellite or create a beautiful aurora. And the jury is still out on what causes these explosions.
Flares, and the related coronal mass ejection, shoot energy, radiation, and magnetic fields out into space that can harm satellites or humans in space. Current observations aren’t precise enough to determine whether the eruptions are driven by energy surging through the sun’s surface, or by the sudden release of energy that has slowly accumulated in the atmosphere.
This aurora over Valkeakoski, Finland on September 15, 2000 resulted from the September 12 coronal mass ejection featured in the video above. › Download video Credit: Tom Eklund
Now, a new way of looking at old data has changed all that, but the results have created more mystery: There isn’t enough energy passing through the surface during the eruption to drive the explosion.
“In some sense, the idea that energy from below triggers the eruption is the easiest explanation – like a geyser,” says Peter Schuck, a physicist who studies space weather at NASA’s Goddard Space Flight Center in Greenbelt, Md. “But if the idea doesn’t agree with what’s observed, then it’s wrong. End of story.”
Schuck’s research indicates that, instead, the trigger occurs in the sun’s atmosphere. “Our result shows that observations are more consistent with a slow accumulation of energy in the atmosphere,” Schuck said, “and then a sudden explosion triggered from above, more like lightning.”
Schuck studies coronal mass ejections, or CMEs, and solar flares at the place where theory and observation overlap. His latest work on CMEs appeared in the Astrophysical Journal on May 1. Schuck constructed a way to test CME and flare observations in order to limit which group of hypotheses fit the data, even when there’s not enough evidence to conclusively pick a single theory.
In the case of CMEs, the data is limited to distant movies captured by spacecraft such as the Solar and Heliospheric Observatory (SOHO). These movies show that CMEs begin as a gigantic arch, some 50 times larger than Earth, with each of its feet planted on the sun’s surface, or “photosphere.”
Two broad camps of theories have been developed to explain these so-called coronal loops. “The energy is built up by either a twisting motion below the surface or the release of magnetic energy in the solar atmosphere,” says Haimin Wang, a physicist at the New Jersey Institute of Technology, whose work focuses on the characteristics of the photosphere before and during solar ejections.
Either way, the energy originally comes from the surface. The question is simply whether it surges through directly before the appearance of the coronal loop or oozes up slowly over time, storing up in the atmosphere until released in a massive explosion of light, plasma, magnetic fields and high energy particles.
Distinguishing between the two options based solely on a distant movie isn’t easy. Imagine trying to figure out what powers a car when all you’ve got to go on is a movie of a highway. Worse, that movie isn’t from above, so you might easily determine the direction and speed of those cars, but from head-on or a side view where you’re not even sure of the angle.
If, however, you can infer the speed of the car, you could at the very least figure out how much energy it has and, in turn, rule out any power source that didn’t jibe with what you saw.
Schuck has done exactly that. “I developed a way to infer magnetic field motion, and therefore energy amounts, from the velocities we observe in the photosphere,” he says.
Imagine the cars again. If the cars were coming directly toward you, you could measure the wavelength of the headlights and by determining how strongly they’d been shifted by the Doppler effect (that same wave-changing effect that causes sirens to sound higher as they come toward you and lower as they move away) you could measure the car’s speed.
Schuck used similar, head-on Doppler measurements to find the velocity of solar material on the surface of the sun. This material moves perpendicular to the magnetic field at the base of the coronal loop — the crux of what Schuck is trying to understand. He can convert those initial velocities of the sun’s surface into information about the motion and energy of the magnetic field. This analysis may not spit out an exact number for the energy, but it does give a precise, accurate range of energy possibilities.
And so, for the first time, one can look at images of the sun and set firm limits on the maximum energy at a given spot – at least if the material was moving directly towards the camera to provide an accurate Doppler measurement.
The next step applies the analysis to an actual coronal mass ejection. Schuck looked at the data from a CME on September 12, 2000. This was an M-class ejection — meaning it was fairly intense, but one step below the strongest X-class — that moved directly towards Earth. Conveniently, this was also a well-studied flare, so other scientists had already examined SOHO images to measure the path, speed, and energy of the CME. This information, in turn, implies how much energy would have come through the photosphere at the start of the process had it indeed initiated from below.
The results were dramatic. The SOHO images showed the photosphere moving at speeds 10,000 times less slowly than would have been expected if it were directly triggering the eruption. “The velocity you’d need to see on the photosphere would be a thousand kilometers per second,” says Shuck. “Not only are these speeds easily detected but they would be greater than the standard measurement range of the instrument. You’d see really weird stuff in the data readouts.”
There is always the slim chance that somehow the instruments didn’t catch the extreme motion, but given how large the velocities would have had to be, Schuck thinks this is unlikely.
This still leaves a variety of theories on just how the energy is stored and what triggers its release in the atmosphere. Distinguishing between those theories will require more detailed data—something scientists hope NASA’s Solar Dynamics Observatory, launched in February 2010 will be able to provide.
Unlike previous missions, SDO will be able to directly measure the energy in the photosphere – as opposed to Schuck’s present method of inferring that energy from velocity measurements — and it will do so with 20 times the resolution of the data on which Schuck based his current work. Such information will help narrow down what triggers a CME or solar flare even more precisely.
“Now we just need some really big CMEs to work with,” says Schuck.
h/t to Dr. Leif Svalgaard
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Leif Svalgaard says:
November 24, 2010 at 3:46 pm
as the ring current dies away after a few days.
The main mechanism of ring current decay is charge exchange of the ring current ions with the geocorona. You can learn more about the physics of the ring current here:
http://www.leif.org/EOS/RingCurrent.pdf
Leif Svalgaard says:
November 24, 2010 at 1:49 pm
The ring current [which is the cause of negative Dst]
But earlier:
Leif Svalgaard says:
November 24, 2010 at 1:46 pm
The physics is this:
The negative part of Dst is determined by how much southward heliospheric magnetic field there is and that is in turn determined by how much magnetic flux on the surface of the Sun there is, which in turn is determined by how many spots there are.
Seems to me the ring current lies nearer the end of the chain of cause and effect than the start. It looks like it fits between the southward heliospheric magnetic field that induces it, and the negative part of the Dst it causes.
Correct?
James F. Evans says:
November 24, 2010 at 3:48 pm
Dr. Svalgaard wrote: “This is because electric fields depends on the observer, but magnetic fields to not.”
False.
If in one reference frame [one observer O] the electric field is E and the magnetic field is B, the electric field E’ and the magnetic field B’ in another reference frame [another observer O’] are given by E’ = E + V x B and B’ = B where V is the velocity of O’ relative to O. Thus the magnetic field does not depend on the observer, but to speak about an electric field without specifying the frame of reference is meaningless. (Alfven and Falthammer, 1963, page 33).
Tell that to all the scientists (including the ones named above)
Double layers indeed exist, but have nothing to do with the reconnection process and are not fundamental building blocks.
tallbloke says:
November 24, 2010 at 5:11 pm
Seems to me the ring current lies nearer the end of the chain of cause and effect than the start. It looks like it fits between the southward heliospheric magnetic field that induces it, and the negative part of the Dst it causes.
Can’t figure out what you mean. The southward component of the HMF controls the amount of energy fed into the Earth’s magnetosphere some of which [in a complicated way] end up as energy of ions [some from the solar wind and some pulled up from the ionosphere] in the [outer] Van Allan belt [the ring current]. Those ions drift around the Earth in its magnetic field while at the same time bouncing between the north and south poles and that constitutes an electrical current around the Earth. The magnetic effect at the surface of the Earth of that current we call Dst [the negative part, because the magnetic effect at the equator is opposite to the horizontal magnetic field there]. Because of collisions with the [way] upper atmosphere the ions are quickly [within hours and days] lost again and Dst reverts to its base level.
James F. Evans says:
November 24, 2010 at 3:48 pm
Dr. Svalgaard wrote: “This is because electric fields depends on the observer, but magnetic fields to not.”
False.
If in one reference frame [one observer O] the electric field is E and the magnetic field is B, the electric field E’ and the magnetic field B’ in another reference frame [another observer O’] are given by E’ = E + V x B and B’ = B where V is the velocity of O’ relative to O. Thus the magnetic field does not depend on the observer, but to speak about an electric field without specifying the frame of reference is meaningless. (Alfven and Falthammer, 1963, page 33).
An example of this is the solar wind hitting the Earth. In the reference frame of the solar wind, the electric field E is zero and the magnetic field is 5 nT, moving towards the Earth at V = 400 km/s = 400,000 m/s. Seen from the Earth [or a spacecraft near the Earth] there is thus an electric field E’ in the solar wind of E’ = 0[E] + 400,000[V] * 0.000,000,005[B] = 0.002 Volt/meter.
Evans wrote: “Tell that to all the scientists (including the ones named above)”
Dr. Svalgaard responded: “Double layers indeed exist, but have nothing to do with the reconnection process and are not fundamental building blocks.”
Per the NASA conference on Double Layers in Astrophysics, it’s clear many presenters do subscribe to the idea that double layers are a fundamental building block.
Apparently, Dr. Svalgaard still can’t bring himself to compare the physical perameters discussed in the two sets of papers, above, double layers and “magnetic reconnection”, respectively.
Perhaps, I know why.
Hannes Alfven, NASA conference:
“B. Magnetic Merging — A Pseudo-Science
Since then I have stressed in a large number of papers the danger of using the frozen-in concept. For example, in a paper “Electric Current Structure of the Magnetosphere” (Alfv6n, 1975), I made a table showing the difference between the real plasma and “a fictitious medium” called “the pseudo-plasma,” the latter having frozen in magnetic field lines moving with the plasma. The most important criticism of the “merging” mechanism of energy transfer is due to Heikkila (1973) who with increasing strength has demonstrated that it is wrong. In spite of all this, we have witnessed at the same time an enormously voluminous formalism building up based on this obviously erroneous concept. Indeed, we have been burdened with a gigantic pseudo-science which penetrates large parts of cosmic plasma physics. The monograph CP treats the field-line reconnection (merging) concept in I. 3, II. 3, and I1.5. We may conclude that anyone who uses the merging concepts states by implication that no double layers exist.”
To highlight: “We may conclude that anyone who uses the merging concepts states by implication that no double layers exist.”
No wonder Yamada, et. al., never mention double layers since they apparently subscribe to the opinion double layers don’t even exist.
Magnetic merging is simply another name for the concept of “magnetic reconnection”.
So, there is a great void between the two scientific schools of thought. Each school holds mutually exclusive opinions. I guess we know what school Dr. Svalgaard resides in.
James F. Evans says:
November 24, 2010 at 7:27 pm
Dr. Svalgaard responded: “Double layers indeed exist”
Alfven: To highlight: “We may conclude that anyone who uses the merging concepts states by implication that no double layers exist.”
Are you not a bit inconsistent here?
So, there is a great void between the two scientific schools of thought. Each school holds mutually exclusive opinions.
There is no two schools of thought. No scientist doubts that magnetic reconnection is the fundamental process. And no scientists subscribes to the EU.
Tell us now what powers the Sun. Or are you afraid to do that?
Leif Svalgaard says:
November 24, 2010 at 5:41 pm
The southward component of the HMF controls the amount of energy fed into the Earth’s magnetosphere
There was a NASA article on WUWT a while back that which said a new discovery had been made that the rate of reconnections (and thus energy flow) between the Sun and Earth’s magnetosphere wasn’t just just down to the southward component but depends on the rate of fluctuation between southward and northward polarity. I can’t find it at the moment, can you remember it?
I fully accept what you are saying about the ring current dropping to a lower base level between these bouts of fluctuation, but it seems clear the average level of the ring current is proportional to the level of solar activity indicated by sunspot numbers, as you earlier statement in response to my graph showing the close correlation between negative Dst and sunspot numbers shows.
You said:
The physics is this:
The negative part of Dst is determined by how much southward heliospheric magnetic field there is and that is in turn determined by how much magnetic flux on the surface of the Sun there is, which in turn is determined by how many spots there are.
tallbloke says:
November 24, 2010 at 11:50 pm
There was a NASA article on WUWT a while back that which said a new discovery had been made that the rate of reconnections (and thus energy flow) between the Sun and Earth’s magnetosphere wasn’t just just down to the southward component but depends on the rate of fluctuation between southward and northward polarity.
That ‘new’ discovery was just usual NASA hype. This is not new at all. The issue is that since the magnetosphere has a certain size cross section, the amount of southward field varies across the magnetosphere and the will be patches where the reconnection is good and other patches where it is bad. See page 32 of http://www.leif.org/research/suipr699.pdf
I fully accept what you are saying about the ring current dropping to a lower base level between these bouts of fluctuation, but it seems clear the average level of the ring current is proportional to the level of solar activity indicated by sunspot numbers, as you earlier statement in response to my graph showing the close correlation between negative Dst and sunspot numbers shows.
My ‘complaint’ was about your statement that there would be a cumulative effect on Dst. There isn’t as the ring current returns to its base level after a few days.
Thanks for the document Leif. So Dst relates to the Am index too, which is used in reconstructing solar wind, hence the relationship. Good match at the modern instrumental end in places. I wonder what the residual will look like between DST pos and neg when subtracted out from SSN and solar wind instumental. I’ll play with that when I get the chance.
Re your ‘complainr’. I didn’t say there was a cumulative effect on Dst. I think there is a cumulative effect on the oceans from something that covaries with SSN. Whether that is electromagnetic effects on cloud cover level I’m not sure yet.
Regarding cumulative effects on Earth’s magnetic field; something causes it to change over the centuries in ways related to longer term solar variation if the 10Be record is telling us anything. Maybe changing solar activity levels and the related repeated rising and falling of the ring currents in the Van Allen belts have an effect analogous to stroking a pin with a magnet repeatedly in the same direction, causing ‘field lines’ to align and strengthen the field. Then at other times the ‘stroking’ works the opposite way to de-magnetise the field a bit.
tallbloke says:
November 25, 2010 at 3:41 am
So Dst relates to the Am index too, which is used in reconstructing solar wind, hence the relationship.
No, Dst and Am [and aa and ap] are different animals. Am depends strongly on solar wind speed while Dst does not. It is precisely that difference that makes it possible to separate the effect of the magnetic field and the solar wind speed and thus determine both.
Regarding cumulative effects on Earth’s magnetic field; something causes it to change over the centuries in ways related to longer term solar variation if the 10Be record is telling us anything.
The solar wind magnetic field does not have any effect on the Earth’s main field [generated in the core]. For one, the Earth’s field is 10,000 times stronger, and secondly there is something called the skin effect that prevents changes to penetrate a conductor [which the upper mantle is]. The 10Be record depends on the Earth’s field [and on climate too, BTW], not the other way around.
Leif Svalgaard says:
November 25, 2010 at 3:48 am
Dst and Am [and aa and ap] are different animals. Am depends strongly on solar wind speed while Dst does not.
Yet there seems to be quite close covariance at times, but not at times when neg Dst isn’t covarying with SSN very closely either. Which is interesting, and maybe worth investigating a bit to see if one effect tending to take Dst values strongly towards one sign gets ‘robbed’ by a competing force from the other variable. e.g. strong solar wind when SSN is high.
tallbloke says:
November 25, 2010 at 6:27 am
Yet there seems to be quite close covariance at times, but not at times when neg Dst isn’t covarying with SSN very closely either.
The real relations are with the magnetic field [B] for Dst and with the product of B and the square of the solar wind speed [V] for am ( am = 1/6*B[nT]*(V[km/s]/100)^2 ). B varies closely with SSN, but not perfectly [e.g. cycle 20]. All this is reasonably well understood [to the point where we can derive B and V from Dst and am].
Dr. Svalgaard responded: “Double layers indeed exist”
Alfven: To highlight: “We may conclude that anyone who uses the merging concepts states by implication that no double layers exist.”
Dr. Svalgaard commented: “Are you not a bit inconsistent here?”
It’s not about consistency, and not about my consistency in any event.
It’s about Dr. Svalgaard’s credibility.
The reason Dr. Svalgaard states that, “Double layers indeed exist”, is because the scientific evidence for the existence of double layers is overwhelming. To out-right deny the existence of double layers in the face of the overwhelming evidence for their existence would damage Dr. Svalgaard’s credibility as an objective scientist.
So, Dr. Svalgaard acknowledges the existence of double layers.
But what does that mean?
The issue isn’t whether double layers exist or not (although, hard-core “reconnection” specialists likely do reject DL’s existence, but since they never write about DL’s in their published papers, it’s hard to get their denial on record), rather, the issue is where do double layers exist and under what physical circumstances and what is the result of double layers where they do exist.
Do double layers do anything?
In that context, you realize Dr. Svalgaard’s acknowledgment of double layers existence is just a “throw away line” with little meaning.
The following questions try to put Dr. Svalgaard’s acknowledgment in proper context:
Dr. Svalgaard, do double layers exist in space? And, if so, under what circumstances do double layers exist in space? What parts of space do double layers exist in? Are there limitations on what parts of space double layers exist in? And, what is the result of the presence of double layers in space?
So, the issue isn’t about my consistency, the issue is the extent of Dr. Svalgaard’s acknowledgment of the existence of double layers: In the laboratory only? In the ionosphere in association with auroral processes only? In interplanetary space only?
Remember, Dr. Svalgaard won’t repond to the two sets of papers, double layer and “magnetic reconnection”, that I presented.
Evans wrote: “So, there is a great void between the two scientific schools of thought. Each school holds mutually exclusive opinions.”
Dr. Svalgaard responded: “There is no two schools of thought. No scientist doubts that magnetic reconnection is the fundamental process. And no scientists subscribes to the EU. Tell us now what powers the Sun. Or are you afraid to do that?”
Dr. Svalgaard’s statement is really a series of statements and when you break it down you realize how silly his statements are.
“There is no two schools of thought.”
Obviously, there are two schools of thought with irreconcilable views. The NASA conference on Double Layers in Astrophysics demonstrates that reality.
Why would Dr. Svalgaard make such an obvously false statement?
Because Dr. Svalgaard wants to maintain the edifice of one monolithic body of scientists when in fact scientists are divided on this issue into rival camps. Also, Dr. Svalgaard doesn’t want to be placed into the “reconnection” camp because then his numerous obfiscations are easy to understand and his opinion can be written off.
“No scientist doubts that magnetic reconnection is the fundamental process.”
Again, obviously there are scientists who doubt “magnetic reconection” is a fundamental process, or even a process at all. But once it’s acknowledged that there are numerous doubters in scientific circles, then Dr. Svalgaard can’t act as the “gatekeeper” of scientific wisdom on this website regarding the issues discussed in this comment thread — rather, Dr. Svalgaard is only one of many scientists in a field with various opinions — his opinion carries no special weight.
“And no scientists subscribes to the EU.”
All of the arguments I’ve presented, here, on this comment thread are independent of EU. Rather, all the arguments are based on basic plasma physics — all demonstrated & verified in the laboratory and/or in situ satellite probes.
Dr. Svalgaard rolled out a guilt by association ploy, which is a type of smear.
“Tell us now what powers the Sun. Or are you afraid to do that?”
I already answered your question. I don’t know.
What I do know is that there are unexplained anomolies.
“Or are you afraid to do that?””
This response, considering I already answered the question is the hight of hypocrisy.
Why? Because Dr. Svalgaard has repeatedly refused to specifically compare & contrast the two sets of paper I previously presented.
Dr. Svalgaard knows Double Layers and “magnetic reconnection” are the same physical phenomena, but the Double Layer analysis & interpretation has been qualitativley & quantitatively fully resolved into a robust formalism (mathematical equations), while “magnetic reconnection” hasn’t and never will be fully quantitized because it is a failed concept that doesn’t have a basis in reality.
Dr. Svalgaard, are you afraid to compare & contrast the two sets of papers I presented which stand for the proposition that Double Layers and so-called “magnetic reconnection” are actually the same physical phenomena?
So-called “magnetic reconnection” fails because historically it omited discussion of charged particle currents — this is changing by necessity — but as charged particle flows have been observed & measured by “reconnection” proponents, it’s apparent double layers and “magnetic reconnection” have the exact same charged particle flows.
This is where the rubber meets the road:
Electric double layers and “magnetic reconnection” have the same charged particle movements.
Dr. Svalgaard knows this to be true so he refuses to compare & contrast the two sets of papers.
Dr. Svalgaard, if the charged particle current flows are not the same, please explain how the charged particle currents are different.
A passage from Hannes Alfven’s NASA presentation:
“Phenomena which can not be understood without explicitly accounting for the current [movement of charged particles] are:
1. Formation of double layers.
2. Energy transfer from one region to another.
3.The occurrence of explosive events such as solar flares , magnetic substorms, possibly also “internal ionization” phenomena in comets (Wurmet et al., 1963; Mendis, 1978), and stellar flares.
4. Double layer violation of the Ferraro corotation. Establishing “partial corotation” is essential for the understanding of somefeatures of the solar system.
5. Formation of filaments in the solar atmosphere in,the ionosphere of Venus, and in the tails of comets and in interstellar nebulae.
6. Formation of current sheets which may give space a “cellular structure.”
Exploration of those plasma properties which can be described by the magnetic field concept has in general been successful. However, this is not the case for those phenomena whch can not be understood by [mapping the magnetic field] this approach.”
Mapping charged particle movement is the key to understanding this phenomena.
The double layer analysis & interpretation explicitly maps charged particle movements.
So-called “magnetic reconnection” does not. That is why “magnetic reconnection” is a failed paradigm.
James F. Evans says:
November 25, 2010 at 9:58 am
So-called “magnetic reconnection” does not. That is why “magnetic reconnection” is a failed paradigm.
I give up. It is like trying to get somebody off the fixation that the Earth is only 6000 years old.
Dr. Svalgaard, you should give up — because the scientific evidence demonstrates your opinion is wrong — that’s why you can’t respond to specific questions about specific physical phenomena.
But more important, the empirical observations & measurements will decide who’s opinion is valid.
Getting back to the question at hand:
What causes coronal mass ejections to form & propagate?
Where does the energy come from for CME formation & propagation?
The power of plasma physics is that laboratory experiments can quantify the process of exploding double layers in high resolution as expressed in mathematical formalism, i.e., mathematical equations.
Thus, the mapped profile of the movement of charged particles per the Electric Double Layer analysis & interpretation can be predicted — the exploding double layer hypothesis, then, can be TESTED — and if the prediction and the actual observations & measurements of the motions of charged particles are the same, then the hypothesis of exploding double layers has been verified.
With the advent of the SDO, the formation of CME’s can be quantified in high resolution. In other words, magnetic fields, electric fields & charged particles’ location, direction, and velocity (currents) & charged particles’ location of acceleration can be mapped to a high degree of resolution.
The movement of the charged particles can be mapped.
Compare & contrast the physical dynamics of exploding double layers as observed & measured in the laboratory and predicted for the formation and propagation of CME’s with the actual observed & measured formation and propagation of CME’s.
Once CME’s are resolved, then the comparison between the two processes should be simple enough.
My prediction: The movement of charged particles, the magnetic fields & electric fields will be the same for the predicted exploding double layer model and the actual observations & measurements of the formation & propagation of CME’s.
If my prediction turns out to be right:
Then what is your opinion going to be, Dr. Svalgaard?
REPLY: Sheesh, it’s Thanksgiving, lighten up. – Anthony
James F. Evans says:
November 25, 2010 at 11:10 am
Dr. Svalgaard, you should give up — because the scientific evidence demonstrates your opinion is wrong — that’s why you can’t respond to specific questions about specific physical phenomena.
OK, you then have earned the right to get your nose rubbed in it.
If magnetic reconnection is a failed paradigm show us a list of authors and their papers that say specifically that. Since in the last ten years we have obtained so much high-quality in situ data, you can limit yourself [eases your work finding all these references] to the last ten years.
The specific issues are lost on you as we have seen so often.
Leif Svalgaard says:
November 25, 2010 at 12:13 pm
If magnetic reconnection is a failed paradigm show us a list of authors and their papers that say specifically that. Since in the last ten years we have obtained so much high-quality in situ data, you can limit yourself [eases your work finding all these references] to the last ten years.
The specific issues are lost on you as we have seen so often.
If you are a scientist then you should have no problem going to the LAPD plasma experiments and looking at the aforementioned paper, and tracing from first cause the reason for the formation of flux tubes.
In a laboratory Flux tubes form because the local plasma cannot carry the current required to equalize the charge differences between two areas(anode, cathode).
The evolution is very interesting because what happens in the high current discharge is first the flux tube or filament pair forms following the right hand rule.
Next when the current exceeds a certain threshold the Biot-Savart forces change(gyroradius) and attraction between the filaments allows them to touch.
You then have a changes in current direction where the current now returns along the adjacent filament. This causes a double layer to form at the junction of the return current between the 2 filaments. Bam! reconnection as you call it. I call it a filamental pinch…. Jets out.
Now this section of the filament is cut from the rest of the filaments leading to “multiple reconnection sites”.
Looking at one small section. What happens is the magnetic field now collapses leading to a field aligned current being driven allowing the reformation? of the filament and the dissipation of current into the load.
This is exactly what CLUSTER sees if you read all of the papers especially on FTE’s.
Process starts over.
So how does that fit with the MHD 2D viewpoint?
BRANT says:
November 25, 2010 at 1:28 pm
In a laboratory Flux tubes form because the local plasma cannot carry the current required to equalize the charge differences between two areas(anode, cathode).
But since in space there are no anodes or cathodes the comparison limbs badly.
The currents in space plasma are caused by neutral plasma moving across magnetic fields. Your cite says “Results are presented from an experiment in which two plasmas, initially far denser than a background magnetoplasma, collide as they move across the magnetic field. […] A reconnection event is triggered by the collision and the electric field induced in this event generates a field-aligned current, which is the first step in the development of a fully three-dimensional current system”
So, pressing neutral, magnetized plasmas together leads to reconnection which in turn induce electric currents, etc. This is how everything fits nicely into the reconnection paradigm.
BRANT says:
November 25, 2010 at 1:28 pm
So how does that fit with the MHD 2D viewpoint?
As the paper says: “An intense current channel generated by magnetic field reconnection occurs when the plasmas collide”.
My mistake. Here is the paper before that one.
You can see the experimental setup. The laser hits the target producing lpp.
Streams of electrons are electric currents which produce the flux tubes.
I dont think you can produce flux tubes with induction in space because the magnetic fields involved are too weak to induce the required current. Actually, I would like to see that experiment on earth. Any references??
Visualizing Three-Dimensional Reconnection in a
Colliding Laser Plasma Experiment
EXPERIMENTS on the dense laser-produced plasmas (lpp) expanding into a background magnetoplasma trigger a rich variety of phenomena including the formation of magnetic bubbles [1] and the generation of Alfvén waves [2], [3]. The lpp
emit streams of field-aligned electrons, which, in turn, generate return currents in the background plasma. Within several microseconds, these become the current systems of shear Alfvén waves. The currents merge and split in space and time and are
peppered with regions in which magnetic fields that point in opposite directions are forced together. The data indicate that they are likely the sites of magnetic field-line reconnection.”
We stress that this is a reconnection mediated by the current systems of Alfvén waves. It is the motion of these currents/waves that force magnetic field lines together and trigger local reconnection.
http://plasma.physics.ucla.edu/papers/Gekelman_Recon_IEEE2008.pdf
And here is the Galley of experimental data.
http://plasma.physics.ucla.edu/pages/gallery.html
The sun is emitting flux tubes of all sorts. There are flux tubes that connect the sun and the earth. The amount of power transferred by any of these events must have a effect on the earth’s climate.
brant says:
November 25, 2010 at 3:43 pm
We stress that this is a reconnection mediated by the current systems of Alfvén waves. It is the motion of these currents/waves that force magnetic field lines together and trigger local reconnection.
Sure, it is hard in the lab to force magnetic field lines together. It helps to have some currents. Even to produce the plasma in the first place.
The sun is emitting flux tubes of all sorts. There are flux tubes that connect the sun and the earth. The amount of power transferred by any of these events must have a effect on the earth’s climate.
This is not quite what happens. The Sun emits hot magnetized plasma. The solar wind has here and there what is known as a tangential discontinuity where the magnetic field changes direction. Such places are ‘neutral sheets’ and drift currents [that do not transfer power] occur there. The mother of all such current is the heliospheric current sheet: http://wso.stanford.edu/gifs/helio.gif
The power of the solar wind is less than a millionth of that of the ordinary heat and light emitted by the Sun, on par with the power in moonlight, which scarcely have much climate impact.
Leif Svalgaard says:
November 25, 2010 at 5:31 pm
The power of the solar wind is less than a millionth of that of the ordinary heat and light emitted by the Sun
Leif, thinking back to our discussion where you said the solar wind was much stronger at the earlier stages of development of the solar system. Has there been any effort to model the effects of the spin-orbit couplings in that early regime? I’m wondering if the planets and sun have the odd ‘coincidences’ in their orbits and periodicities because of the left over coupling effects from the time when the strong coupling existed. My hypothesis is that the rhythm the planets and sun settled down into regulated the rate of solar output, and that stars without big Jovian type planets are more likely to go runaway and have shorter lives ending in supernovae.
Who would be a good person to ask about this stuff?
Thanks
tallbloke says:
November 25, 2010 at 9:22 pm
Leif, thinking back to our discussion where you said the solar wind was much stronger at the earlier stages of development of the solar system. Has there been any effort to model the effects of the spin-orbit couplings in that early regime?
There is no spin-orbit coupling except that due to tidal interactions and they have always been much too small in case of the sun. There is, however, a very strong magnetic coupling which brakes the sun from rotating in a day to 25 days and transfer the angular momentum to the planets with the result that they end up with some 98% of the total angular momentum of the solar system. This took place very early on and the process is not operating any more.
I’m wondering if the planets and sun have the odd ‘coincidences’ in their orbits and periodicities because of the left over coupling effects from the time when the strong coupling existed.
The planets likely ‘migrated’ all over the place in the early solar system, but that has now stopped [except perhaps for Pluto].
My hypothesis is that the rhythm the planets and sun settled down into regulated the rate of solar output, and that stars without big Jovian type planets are more likely to go runaway and have shorter lives ending in supernovae.
The planets have never regulated anything since the early days. The supernovae are not caused by any planetary action or lack thereof, but either by a large star [several times more massive than the Sun] running out of fuel and losing the inner furnace once the interior has been burned into iron, or by a smaller star in a binary system swelling to become a red giant and then the other star [already burned out to a white dwarf] siphoning off gas from the swelling star. Since there is an upper limit to the mass of a white dwarf [the more massive it gets, the smaller it becomes until reaching zero size for a mass of 1.4 times the Sun’s – the Chandrasekhar limit] this process [stealing the other star’s gas] causes the star to explode as a supernovae. This type of supernova is thus always of the same ‘strength’ and can be used as a ‘standard candle’ for determining the distance to the galaxy in which it occurs.
Who would be a good person to ask about this stuff?
Any astronomer would know. All this is textbook stuff. You could even ask me 🙂
Leif Svalgaard says:
November 25, 2010 at 9:38 pm
There is, however, a very strong magnetic coupling which brakes the sun from rotating in a day to 25 days and transfer the angular momentum to the planets with the result that they end up with some 98% of the total angular momentum of the solar system. This took place very early on and the process is not operating any more.
The planets have never regulated anything since the early days.
Yes, I want to Work this one through as the null hypothesis. I’m interested to discover if any effort has gone into modeling the early solar system to recreate this process of EM coupling which transferred the energy from the sun to the planets, to see if that process develops a resonance amplified rhythm.
Your comment further upthread that the solar wind is denser when slower is interesting too.
The flow pressure increases when the density increases [and that, in turn, varies inversely with solar wind speed – low speed wind is denser]
In the early solar system would periods of low windspeed have increased the EM entrainment and angular momentum transfer?