Magnetic reconnection and physical processes

[Michael Mozina]

You seem to think that the core field of flux tubes is generated by charges circling around that field.

No. It's created by the electrons that flow through the plasma tube!

http://en.wikipedia.org/wiki/Birkeland_current

Birkeland currents can also be created in the laboratory with multi-terawatt pulsed power generators. The resulting cross-section pattern indicates a hollow beam of electron in the form of a circle of vortices, a formation called the diocotron instability[3] (similar, but different from the Kelvin-Helmholtz instability), that subsequently leads to filamentation.

 

[Michael Mozina]

From the paper by Bruce:

(2.1) Solar Prominences

The theory may be said to have started with a successful prediction during Sydney Chapman's Kelvin lecture(3.1) on the sun to the Institution of Electrical Engineers on 8th May, 1941, when he referred to a solar prominence which had reached a height of a million miles in an hour. It seemed to the writer that this could only mean that the phenomenon must be a solar lightning flash and that, therefore, a million miles an hour must be equivalent to 3 x 107 cm/sec, the velocity of propagation of the lightning leader-stroke since the velocity of propagation of breakdown in a gas should be independent of the density. A little mental arithmetic in the darkness corroborated on a scrap of paper when the lights went up, verified that this first prediction was approximately correct and the electrical discharge theory was launched. It soon appeared(2.7) that this prominence could not be an isolated electrical discharge but that all the solar "surface" phenomena must be electrical; that the granulations of the photosphere, the spicules of the chromosphere and the rays of the corona, form a hierarchy of electrical discharges at decreasing gas densities and increasing discharge temperatures.

Rhessi and Fermi both demonstrate that discharge in the Earth's atmosphere produce exactly the same gamma ray radiation as discharges in the solar atmosphere.

 

[Tim Thompson]

Alfven Was wrong!! II

As Alfven explained, not a single magnetic line disconnects or reconnects to any other magnetic line, so it is irrational to call it "magnetic reconnection".

Alfven was wrong. Einstein was wrong too, and neither of them are accused of being dummies by anyone. Not dummies, just wrong. Since when does a Nobel Prize, or just plain genius, confer infallibility on anyone?

Einstein was one of the brilliant minds who established the foundations of modern physics almost single handedly. He was the father of both special & general relativity, and one of the founding fathers of quantum mechanics. In fact, it was quantum mechanics, and not relativity, for which Einstein received his Nobel Prize (1921). But while he might have been a rebel visionary in his youth, he lost that quality later in life. He spent decades on his lonely quest for unified field theory, doomed to fail because he had entirely rejected the quantum physics that he had himself helped too invent, and championed in his youth. He was a genius or close to it, but lost his way in the end, a fate that befalls fallible people.

Alfven may or may not have been as brilliant as Einstein, but he was certainly just as fallible. He established plasma physics almost as single handedly as Einstein had established modern physics, and Alfven also got a Nobel Prize for his efforts (1970). But Alfven was no more able to handle the advances in physics after his most productive period than was Einstein. Just as Einstein's invention, quantum mechanics, left him behind, so did Alfven's invention, MHD, leave him behind.

I know this because I know a great deal more about physics in particular, and science in general, than you do. You reject without thought or reason every idea that does not fit into your own personal religious concept of the way thing ought to be. Everybody except you can see that as plain as day. You redefine words like "science", "empirical" and "physics" to suit some secret whim of your own, completely ignoring the fact that the rest of the world means something quite different than you do when we use those words. There is no use in even trying to present real evidence too you, because you always thoughtlessly reject everything presented; you won't touch or consider a single paper or single book or single idea in physics that disagrees with your preconceived notion.

I have already presented plenty of evidence for the reality of magnetic reconnection and you have instantly and thoughtlessly rejected it. I gave you controlled laboratory experiments (Comments on Magnetic Reconnection) and you didn't even bother to look at them or think about them for 10 seconds. After demanding them, you rejected them, for purely religious, unscientific reasons. Likewise and without reference to any real physics, you reject every notion of magnetic reconnection on the grounds of pure & 100%, anti-scientific, philosophical bias.

It's all right here: Magnetic Reconnection: MHD Theory and Applications by Eric Priest & Terry Forbes, Cambridge University Press, 2000. If you are too lazy or too illiterate to read a physics book, I can't help you.

And finally, I repeat what I have already said before:

So, how about a show of hands from Michael Mozina:
Have you read Magnetic Reconnection: MHD Theory and Practice by Priest & Forbes?
Have you read Nonlinear Magnetohydrodynamics by Deiter Biskamp?
Have you read Fundamentals of Plasma Physics by Paul Bellan?
Have you read The Physics of Plasmas by T.J.M. Boyd & J.J. Sanderson?
Have you read Plasma Physics for Astrophysics by Russell Kulsrud?
Have you read Plasma Astrophysics by Toshiki Tajima & Kazunari Shibata?
Have you read Conversations on Electric and Magnetic Fields in the Cosmos by Eugene Parker?

If you have not read any of these, can you tell us what plasma physics books, other than Alfven, you actually have read?
How many plasma physics classes have you taken?
How many plasma physics laboratory experiments have you performed yourself, or assisted with?

How much of what you say is based on ignorance and how much is based on knowledge? if you have never read a book on plasma physics besides those of Alfven, then how in the world would you be in a position to fairly teach anybody anything about plasma physics? Remember, you did say you could teach us a lot about physics. Well, we are still waiting.

 

[Tim Thompson]

Magnetic Reconnection Redux IX

So now your "magnet reconnection" is magnetic reconnection?

No, it's always "magnet reconnection". Stop hijacking this thread!

How can somebody hijack a thread on magnetic reconnection by talking about magnetic reconnection? Chill out, dude.

None of this has anything to do with solar physics.

Perhaps not directly, but it does have to do with magnetic reconnection, and the title of this thread is "Magnetic reconnection and physical processes", and that makes it relevant. Besides, have you not constantly insisted that magnetic reconnection (the reconfiguration of the topology of a magnetic field) is impossible? If it is impossible, then it is impossible, period. Introducing the complications of plasma physics only allows you to hide behind the resultant complications and ignore the real issue at the level of real physics, namely the physical process of magnetic reconnection.

No "reconnection" between the fields ever actually occurs if you never touch the magnets together, and we can measure the field after the process and field each of them is exactly the same as before the energy conversion process.

A completely correct and totally irrelevant observation. Hold two magnets far apart under paper with iron filings (or the functional equivalent) on it. Move the magnets so they slide close past each other and you can see the magnetic field topology change before your very eyes, visualized by the iron filings. There may even be a video of such things out there (or some enterprising reader can make one). The fields reconnect & disconnect. They are not visibly different before & after the event, but it's what happens during the event that counts. That's when the fields reconnect. And if those fields can reconnect, then fields immersed in a conductive plasma will certainly reconnect as well (which everyone except perhaps yourself & Zeuzzz understands quite well).

 

[Tubbythin]

How can somebody hijack a thread on magnetic reconnection by talking about magnetic reconnection?

Its incredibly funny that Michael should criticize anybody for hijacking a thread, especially when he has another thread explicitly with his name in the title which was created to stop his hijack of another thread.

 

[tusenfem]

It's not "my model", it's "Alfven's/Bruce's/Birkeland's" model.

http://www.thesurfaceofthesun.com/A...r Atmosphere And A Theory Of Solar Flares.pdf

In Alfven's paper, he's turning that "flux tube" into a part of a "circuit" and when the "circuit" is disrupted, that "magnetic energy" is released. It's a z-pinch that ultimately creates the current disruption process.

I have already talked about that paper I think. It is one of the first that describes the creation of a double layer through a density dip in the flux tube. In another paper by A&C they describe the unwinding of a flux tube though the creation of a double layer, which they say is a flare. In the last part of this paper they show, using a circuit that the total circuit energy is enough to explain the energy released in flares. Nothing against that as it has been shown that calculating the electromagnetic energy of the loop through the E and B fields is compatitle with the RLC description of a circuit.

Then they describe the "explosion of the magnetic field" but basically there is a very strong electric field in a very low density plasma. But no real discussion is given how exactly the "vacuum diode" model relates to the flare, only that the energy of the circuit is enough for observed energies.

So, it may be Alfven's model, but you defend this model, so it is also yours, as Alfven cannot defend it anymore. However, there is still no "circuit reconnection" model presented anywhere.

The particles in the tube "fly off" away from the tornado like filament due to the current disruption. The release of energy is directly related to the current flow and the disruption of that current flow through the "magnetic rope". Alfven is most certainly using that "rope' as the conductive equivalent of a "wire". When the current flow creates a z-pinch in the tube, the whole thing "explodes".

What "tornado like filament"? How does this explosion happen? In the other A&C paper (or C&A I don't know at the moment) they describe ONLY the unwinding of the flux tube through the creation of the double layer in the loop.
The whole discussion in the paper is about the maximal current a plasma can carry without becoming unstable (and create e.g. double layers), and what then happens. There is not mention of any pinch in this whole paper. Methinks, you don't understand what the paper was about.

Use Maxwell's formulas to convert all your B's into E's.

But what should that do, apart from making the equations way more complicated as we then use E and j. The starting point of the magnetic field is rather simple, the appropriate current system is highly complex as J = curl(B), but it can easily be done. But that still does not make it a circuit description.

So Micheal, it is about time that you do some work yourself, instead of having other peeps do the work for you, read and comment papers for you, so you might understand them better.

And apparently, you found my run through of the paper about the circuit of the solar loop not interesting. Ah, maybe someone else did.

But you might want to look a little bit wider around, than just Alfven and other old stuff, then you would have know that that solar circuit paper was nothing new except for the RHESSI data, and that is probably also the reason that is was published in such an obscure journal.

 

[tusenfem]

No, but everyone agrees that that is it possible for two current carrying magnetic ropes to "reconfigure" themselves. We can't agree on what that process should be called. As Alfven explained, not a single magnetic line disconnects or reconnects to any other magnetic line, so it is irrational to call it "magnetic reconnection".

But that is not the "usual situation."
The situation in the magnetotail it is oppositely directed field separated by a current sheet, how does that jive? Alfven describes almost always the unwinding of a flux tube as a "flare" which is completely different from reconnection, he is discussing a whole other process, without any topological change of the magnetic field as is observed in the laboratory and in space.

 

[tusenfem]

No. It's created by the electrons that flow through the plasma tube!

http://en.wikipedia.org/wiki/Birkeland_current

Oh yeah, again that nonsens part on the wiki page. I don't understand that, could you please explain to me what "The resulting cross-section pattern indicates a hollow beam of electron in the form of a circle of vortices, a formation called the diocotron instability" and then especially the "hollow beam part" means. (I really should edit out all that nonsense from wiki. it would have been nice if the author would have given a reference for this "hollow beam".)

Also, electrons flowing though the tube cannot create the guide field the are flowng along. That is basic electrodynamics, which obviously you don't understand.

Now, let brantc answer the question, maybe he can come up with an answer that makes sense, or are you afraid your pupil will give an answer that does not jive with your misconceptions?

 

[sol invictus]

Not unless the magnets themselves physically reconnect. That's magnet reconnection and has nothing whatsoever to do with solar physics.

I don't understand what you mean. The magnets are physically separated, with vacuum (plus magnetic field) in between them. They don't touch.

So let me ask you again: do you deny that the magnetic field lines in between them are reconnecting as they move?

If so, why? We've shown you field configurations like that, we've shown you that they reconnect, and we've shown you that the whole process is both consistent and in fact required by the laws of elecromagnetism. So which part are you objecting to?

Are you still claiming magnetic field lines simply can't reconnect, even after being shown an explicit solution where it happens? If so, what would it take to convince you? Is there any point in discussing it?

 

[The Man]

No, it's always "magnet reconnection". Stop hijacking this thread!

So magnets are still not magnetic for you?


Again discussing the magnetic reconnection of magnets in a thread about “Magnetic reconnection and physical processes” is not “hijacking this thread”. Stop trying to limit this discussion to magnetic reconnection in plasma that you claim isn’t even magnetic reconnection.

 

[The Man]

There is nothing "reconnecting" in your example with the possible exception of the magnets themselves (depending your mood evidently).

What has my mood got to do with it? You’re the one claiming the fields do not reconnect and then saying only if the magnets “touch” do the fields reconnect.

Are you confusing yourself with someone else again?

You're making up the idea that the magnetic fields reconnect, just like you made up the term "spring reconnection" in my spring example. Nothing is "reconnecting". You're just storing energy in the field and releasing it! Nothing RECONNECTS!

Nope, again "spring reconnection" was your made up term and you provided no example, but I did.

Are you confusing yourself with someone else again?


Again storing energy and releasing it is not magnetic reconnection it is specifically the reconfiguring of the fields that allows that energy to be released in a manor not directly opposing the applied energy being stored in those fields.

 

[Michael Mozina]

I don't understand what you mean. The magnets are physically separated, with vacuum (plus magnetic field) in between them. They don't touch.

Then nothing ever "reconnects" either.

So let me ask you again: do you deny that the magnetic field lines in between them are reconnecting as they move?

They do not "reconnect". They simply "interact".

If so, why? We've shown you field configurations like that, we've shown you that they reconnect,

Huh? Where did you show me that the magnetic fields "reconnect" rather than just "store and release energy"? The fields of both magnets are exactly the same both before and after the example. Nothing 'reconnects'. You're simply storing and releasing energy.

 

[sol invictus]

They do not "reconnect". They simply "interact".

No. They reconnect.

Huh? Where did you show me that the magnetic fields "reconnect" rather than just "store and release energy"? The fields of both magnets are exactly the same both before and after the example. Nothing 'reconnects'. You're simply storing and releasing energy.

We had extensive discussions of this here which included a simple, explicit, analytic solution to Maxwell's equations in which the B field lines reconnect (which I think Zig posted first). Perhaps you weren't part of that discussion; I don't recall. I can re-post the solution if you'd like to see it. Should I? Is there any point?

For now, please watch this movie (of a numerical PIC solution to Maxwell in plasma): http://homepage.mac.com/zenitani/files/reconnection.mov

Do you see what the B field lines are doing at the center? That's called "magnetic reconnection". The lines break and reconnect. Do you disagree those lines reconnect? Or do you think this solution is invalid?

 

[Michael Mozina]

No. They reconnect.

No, they don't "reconnect". The magnets either attract or repulse depending on the orientation of the fields. We can demonstrate they don't "reconnect" by putting two north ends toward each other in close proximity. The magnetic fields will not "reconnect", they will continue to repulse each other. If we let them go, they fly apart. All we've done is stored potential energy as magnetic repulsion and we release it again by letting go of the magnet. Likewise if we put a north and south end toward each other, even if we bring them in close proximity, the "magnetic attraction" seeks to pull them together. No matter how close together they get, then continue to "attract" so we know that the fields not not "reconnect". We can pull them apart again, measure each field and they are exactly the same as before. Essentially you're simply mislabeling "magnetic attraction/repulsion" and calling it "magnetic reconnection".

We had extensive discussions of this here which included a simple, explicit, analytic solution to Maxwell's equations in which the B field lines reconnect (which I think Zig posted first). Perhaps you weren't part of that discussion; I don't recall. I can re-post the solution if you'd like to see it. Should I? Is there any point?

Maybe. I'd need to see it to comment. I'll take a look at your movies and comment after I've seen them. In the mean time you might explain how 'reconnection' in TM's example is separate from "magnetic attraction/repulsion".

 

[Michael Mozina]

For now, please watch this movie (of a numerical PIC solution to Maxwell in plasma): http://homepage.mac.com/zenitani/files/reconnection.mov

Do you see what the B field lines are doing at the center? That's called "magnetic reconnection". The lines break and reconnect. Do you disagree those lines reconnect? Or do you think this solution is invalid?

I'm going to need some background on that movie before I can really comment. That could be a form of magnetic repulsion/attraction too for all I know.

 

[Michael Mozina]

Again storing energy and releasing it is not magnetic reconnection it is specifically the reconfiguring of the fields that allows that energy to be released in a manor not directly opposing the applied energy being stored in those fields.

You are simply confusing "magnetic attraction/repulsion" with "magnetic reconnection". At no time do the magnetic fields "reconnect". If we put two norths or two souths together, they continue to repulse each other no matter how close we get them. Likewise we can put a north and south end as close as we like, but the *SEPARATE* magnetic fields will continue to create "magnetic attraction" with the other magnetic field and seek to pull the magnets together. The ruse here is your mislabeling of "magnetic attraction/repulsion" "magnetic reconnection". Nothing "reconnects".

 

[sol invictus]

No, they don't "reconnect".

Stop. What do you mean? Do you mean that the magnetic field lines in the magnet case do not behave like the ones in that movie? Or do you mean that that behavior is not magnetic reconnection?

Maybe. I'd need to see it to comment.

OK, here it is:

Your analogy isn't very good. Let me give you a concrete example of a magnetic field which exhibits reconnection. Consider the field

[latex]$\vec{B} = by\hat{i} + ax\hat{j}$[/latex]

This field satisfies Maxwell's equations for any and all a and b.

Now, if you vary the prefactors a and b, what happens? Well, consider the points (-1,1), (1,1), and (-1,-1), shown by the black dots below. For any a < b, the points (-1,1) and (1,1) will be connected by a magnetic field line, as shown on the left. For any a > b, the points (-1,1) and (-1,-1) will be connected by a magnetic field line, as shown on the right. The field itself varies smoothly as a and b change continuously, but the change in connectivity between those points is still abrupt.
[qimg]http://www.internationalskeptics.com/forums/imagehosting/thum_1192499b6711ad5d6.gif[/qimg]

I'm going to need some background on that movie before I can really comment. That could be a form of magnetic repulsion/attraction too for all I know.

It's a simulation of magnetic fields in plasma. The color is density, and the white lines are magnetic field lines. As you can see, the magnetic field lines are reconnecting. What more background do you need?

 

[Michael Mozina]

Stop. What do you mean? Do you mean that the magnetic field lines in the magnet case do not behave like the ones in that movie? Or do you mean that that behavior is not magnetic reconnection?

I'm saying that in TM's example it is "magnetic repulsion" and "magnetic attraction" at work, and *THAT* behavior is *NOT* "magnetic reconnection". I'll have to look at your math and links now that you've provided some background.

Keep in mind that we all seem to agree that two "magnetic ropes" can and do in fact "reconnect", or more specifically a topology change occurs between the ropes. We only seem to disagree on what to call this process. In your movie model, which particles are transferring energy, and which particles receive them?

 

[The Man]

You are simply confusing "magnetic attraction/repulsion" with "magnetic reconnection". At no time do the magnetic fields "reconnect". If we put two norths or two souths together, they continue to repulse each other no matter how close we get them. Likewise we can put a north and south end as close as we like, but the *SEPARATE* magnetic fields will continue to create "magnetic attraction" with the other magnetic field and seek to pull the magnets together. The ruse here is your mislabeling of "magnetic attraction/repulsion" "magnetic reconnection". Nothing "reconnects".

Nope the ruse again simply remains yours. In the refrigerator magnet example the alternating north south stripes (usually running vertically) on one magnet are connected to those on the other. As long as that configuration remains the same, when ever you slide the magnets over each other horizontally and release them they will always return to that original position (simple storage and release of energy, as well as magnetic attraction). However after the reconnection (once you slide them past a certain point) the fields have reconfigured so that the same alternating north south stripes of one magnet are now connected to different stripes on the other. As a result when the magnets are released they moves forward (not back) to a new position exactly one width of the stripes in the direction of the sliding from the original position. While it is true that this is again a release of stored energy and magnetic attraction, what you seem to be deliberately ignoring (or simply have not realized yet) is that the magnetic domains that are attracting have changed (shifted by one width in the direction of sliding) due to that reconnection. Just simple storage and release of energy, as well as just magnetic attraction can not explain that shifting, it is specifically a reconnection of the magnetic fields.

Also with the compass example the needle is connected to the Earths magnetic field, if you just move the compass around slightly it will remain oriented to the Earth’s magnetic field. When you bring the magnet closer to the compass so that the compass reconnects to the magnetic field of the magnet, then as you move the compass around slightly it will remain connected to the magnetic field of the compass.

Much as you like and continue to profess that magnetic reconnection is just the storage and release of energy or just “magnetic attraction/repulsion” they are clearly distinguishable events. Again anytime you’re done wasting your own time dragging around your stawmen we can actually discuss the reconnection (magnetic or spring).

 

[Reality Check]

Keep in mind that we all seem to agree that two "magnetic ropes" can and do in fact "reconnect", or more specifically a topology change occurs between the ropes. We only seem to disagree on what to call this process. In your movie model, which particles are transferring energy, and which particles receive them?

That is not quite right.
We all (except you) agree that magnetic reconnection exists as a change in magnetic field topology as in Ziggurat' year old post (based on an even older post).

We all agree that there is one paper that explains 2 solar flares as magnetic reconnection between 2 twisted magnetic ropes.

We all (except you) agree that there is a model of solar flares that has magnetic reconnection happening in loops of magnetic flux (coronal loops).

There is no disagreement on what to call this process - it is called magnetic reconnection.

Whatever the process that you have made up and called "circuit reconnection" is, it is not magnetic reconection.