Problems With Magnetic Reconnection

[Tim Thompson]

Real Plasma Physics

Yes Tim I have them all now. Before I even get into the rest of your post, please tell me which specific one of those papers and experiments satisfies Alfven's MR conditions?

None of them do. However, Alfven's conditions are erroneous and therefore irrelevant. Worse, you don't have any idea what Alfven's real conditions are anyway, since you misrepresent them by constantly quoting them shorn of context. Just look at this sentence from Alfven that you regurgitate constantly: "What we have found means that we can describe plasma phenomena inside a finite volume only if no electric current crosses the surface". That sentence cannot possibly be correct as stated and is sheer nonsense. How are charged particles moving around in some volume supposed to "know" or "care" if there is an electric current flowing across some imaginary surface around this volume? How could the current possibly make it impossible to know what the plasma is doing inside the volume? You think that simple sentence is all there is to it and that is proof enough that while the words of Alfven's book might have scrolled before your eyes, comprehension & understanding have yet to scroll past your brain.

Lest we forget ... From Feb 4, 2010

Mozina never responded. Let us be clear on something: it is the physics that Mozina does not understand at any level. It is the physics that Mozina constantly gets wrong. We can never teach Mozina physics because he is immune to learning, already quite convinced that his ignorance is in fact knowledge, he is beyond hope. But that need not apply to others reading this thread. So let me do something I said I would not do, since Mozina will never answer the questions above. Let me explore what Hannes Alfven really says about magnetic reconnection (not surprisingly, Alfven does not say what Mozina claims he says).

The following passages are transcribed from the book Cosmic Plasma by Hannes Alfven; D. Reidel Publishing Co., 1981. All of the emphasis (italics) are Alfven's from the original text, none are mine. First, Alfven addresses boundary conditions.

Page 28, section II.5.1 - Boundary Conditions
"Consider a volume V of space limited by a surface S. The properties of the plasma inside of S depend on the boundary conditions. Thus by changing the current through S, we can change the behavior of the plasma. As was seen in the preceding paragraph, the properties of the plasma depend on the whole circuit in which the current flows. This means that we can describe the plasma inside of S by parameters inside S only if i = 0 everywhere on S.
Hence, even if we know all plasma parameters (like density, temperature and magnetization) at every point inside S, we can describe the plasma properties theoretically only if there is no electric current crossing the surface. Therefore, the boundary problems have to be analysed very carefully."
​

This is a necessary consequence of Alfven's adoption of the circuit formalism for describing the physics of plasmas. He takes the position that it is not possible to properly describe the physics of plasmas by local variables alone, but that one must include the entire circuit, hence his requirement that no electric current can flow into or out of a given volume, if you want to use only local parameters to describe the plasma.

This leads into Alfven's specific statement about magnetic reconnection ...

Page 29, section II.5.3, - 'Magnetic Merging' Theories
"What we have found means that we can describe plasma phenomena inside a finite volume only if no electric current crosses the surface. In the terminology of the magnetic field description, this means that we can describe plasma phenomena inside a finite volume only if the perpendicular component of the curl is zero at every point of the surface."
"All theories of 'magnetic merging' (or 'field line reconnection') which do not satisfy this criterion are misleading or erroneous, and deserve no attention. This does not mean that all papers in which 'magnetic merging' is used are of no interest, because there exist some good papers (e.g., Hill, 1975) in which the term is merely a synonym for "current sheet acceleration".
​

These two paragraphs reveal a serious weakness in Alfven's method, in the context of modern plasma physics, and reveal precisely why Alfven was in fact wrong to reject magnetic reconnection. His statement above was correct, and as far as I know remains correct to this day. He was right to reject magnetic reconnection in the context of the boundary conditions he laid out, but carefully note what Alfven actually says, in Alfven's own words: "All theories of 'magnetic merging' (or 'field line reconnection') which do not satisfy this criterion are misleading or erroneous, and deserve no attention." Alfven did not categorically reject the idea of magnetic reconnection, he only rejected it in cases where his boundary conditions apply. The problem, of course, is that his boundary conditions can be quite unrealistic and do not apply in most cases to real plasma in space, and this is where Alfven fails: Alfven's boundary condition requirements do not necessarily reflect the physical state of real plasmas, either in space, or in the laboratory.

Magnetic reconnection requires oppositely directed magnetic fields. Parallel magnetic fields cannot reconnect. Alfven's boundary conditions establish only parallel magnetic fields and therefore rule out at once all cases where one would expect magnetic reconnection to occur. Hence, Alfven is right to claim that magnetic reconnection will not occur when his boundary conditions are satisfied. But he was wrong to assume that his boundary conditions were physically realistic when applied to real space & astrophysical plasma. He was wrong to require all plasmas to satisfy boundary conditions which automatically rule out magnetic reconnection.

Alfven established faulty boundary conditions because he was guided by a faulty paradigm, namely the circuit paradigm for describing the physics of plasmas. That paradigm has serious limitations. It is still used by plasma physicists today, but has limited application. Alfven's reliance on this circuit formalism may have been good enough to establish the basics of plasma physics and the basics of ideal MHD, but was not good enough to handle the advances that have given us modern plasma physics. None of the modern plasma physics text books I have in my library apply the circuit analogy to plasma physics the way Alfven did. It simply does not apply to realistic space plasma physics in most cases, and we can in fact deal with all cases today using the local parameters of the plasma without appealing to Alfven's limiting boundary conditions.

Now, let me add the caveat that I am not a specialist in plasma physics (although I actually have coauthored one paper in space plasma physics: Bolton, et al., 1989). But I do have a master's degree in physics, I can read plasma physics text books, and most importantly of all, I know when to ask for help. So I acknowledge hints from tusenfem on interpreting Alfven in this case. I don't think I am making any big mistakes here, but feel free to correct any errors (even the little ones).

Finally, once again, I direct the interested reader to the book Magnetic Reconnection: MHD Theory and Application; Priest & Forbes, Cambridge University Press, 2000. Section 4.2 describes the Sweet-Parker mechanism, and section 4.3 describes the faster Petschek mechanism, both of which are reconnection mechanisms that take place in plasma environments which are not allowed to exist under Alfven's restrictive boundary conditions.

Like I said: Alfven established faulty boundary conditions because he was guided by a faulty paradigm, namely the circuit paradigm for describing the physics of plasmas. You and michaelsuede have both fallen into the trap of believing that the circuit paradigm actually describes the physics of plasmas. In fact it does not and indeed cannot describe the actual physics of plasmas because the circuit paradigm does not involve particles & fields. The circuit paradigm is primarily useful as a "bookkeeping" exercise, heuristically describing the flow of energy in a plasma, without regard for the physics involved. Only at the level of particles & fields can we really understand plasma physics. The circuit paradigm is the functional equivalent of the elementary school approach to plasma physics. It's time for you to get out of the primary grades and graduate to adult level plasma physics. As long as you tout the virtues of the circuit paradigm, you are just a grade school student of plasma physics.

 

[Tim Thompson]

Magnetic Reconnection and Double Layers

Circuit theory can explain the irreversible change of magnetic topology, and indeed is the only way one can explain such a change given that fluid models invoke ad hoc resistivity.

Absolutely false. No, circuit theory cannot, under any circumstances, ever describe the change in topology of the field. Topology & shape are not the same thing. The only way you can change the magnetic fields in circuit theory is to change the shape of the field by re-orienting the currents. But changing the topology by rearranging the currents is not physically possible.

MHD theory is incapable of modeling the mechanics of a double layer, and necessarily neglects any mention of them in its models.

Wrong again. See, for instance, Magnetic Reconnection: MHD Theory and Applications by Priest & Forbes, page 468, where electrostatic double layers are included as a source of anomalous resistivity, which is required for magnetic reconnection to happen.

You overestimate the importance of double layers. They cannot provide as much energy as reconnection can because they cannot sustain a large enough cross-layer potential in an astrophysical plasma. Besides, double layers accelerate particles in the wrong direction anyway, perpendicular to the flows initiated by magnetic reconnection.

 

[michaelsuede]

Like I said: Alfven established faulty boundary conditions because he was guided by a faulty paradigm, namely the circuit paradigm for describing the physics of plasmas. You and michaelsuede have both fallen into the trap of believing that the circuit paradigm actually describes the physics of plasmas. In fact it does not and indeed cannot describe the actual physics of plasmas because the circuit paradigm does not involve particles & fields. The circuit paradigm is primarily useful as a "bookkeeping" exercise, heuristically describing the flow of energy in a plasma, without regard for the physics involved. Only at the level of particles & fields can we really understand plasma physics. The circuit paradigm is the functional equivalent of the elementary school approach to plasma physics. It's time for you to get out of the primary grades and graduate to adult level plasma physics. As long as you tout the virtues of the circuit paradigm, you are just a grade school student of plasma physics.

I know you didn't just say that I'm the one who's falling into a trap with my understanding of theory.

This from a guy who thinks an object the size of an asteroid is spinning around at half the speed light, while being made entirely of neutrons, and it is ejecting a beam of light that is visible across galactic distances because the beam is being rotated directly at the earth like a lighthouse.

LOL

By the way, how are those double layers treating you guys in those MHD simulations you run?

 

[Tim Thompson]

Circuit Reconnection?

They tend to start with two "circuits" of current carrying plasma and then they "short circuit" them together! Since they carrying current and the plasma acts as a wire or circuit according to Alfven, you simply are shorting two "current carrying wires' together. So what? That's not 'magnetic' reconnection, that's a "short circuit" between two plasma threads and a "double layer" that forms between them.

That is a fairy tale. Magnetic reconnection only happens when the electric currents are flowing in opposite directions. That means, in your "circuit reconnection" fantasy, the currents bash into each other head on. Head on. So why don't you describe the physics for us, how these two currents manage to merge into another current, gaining energy despite colliding head on. And if that's not enough, how about conservation of energy? How do you explain the final current carrying more energy than the sum of the energies of the input currents? Where does all that extra energy come from (ignoring for a moment the head on collision of the currents)?

 

[michaelsuede]

Absolutely false. No, circuit theory cannot, under any circumstances, ever describe the change in topology of the field. Topology & shape are not the same thing. The only way you can change the magnetic fields in circuit theory is to change the shape of the field by re-orienting the currents. But changing the topology by rearranging the currents is not physically possible.

Yes, it can. And I've provided the relevant papers to show how it can. Stamping your feet and claiming it can't, when it clearly can, is ridiculous.

Wrong again. See, for instance, Magnetic Reconnection: MHD Theory and Applications by Priest & Forbes, page 468, where electrostatic double layers are included as a source of anomalous resistivity, which is required for magnetic reconnection to happen.

Very good! But if you acknowledge the existence of a DL as your source of anomalous resistivity, then why in the hell are you still spending my money on trying to solve the riddle of magnetic reconnection?

Could it be because MHD is completely incapable of modeling the mechanics of a DL? Could it be because you refuse to accept that the plasma parcels in question are part of a circuit and obey Kirchhoff's circuit laws as they do in the lab?

You overestimate the importance of double layers. They cannot provide as much energy as reconnection can because they cannot sustain a large enough cross-layer potential in an astrophysical plasma. Besides, double layers accelerate particles in the wrong direction anyway, perpendicular to the flows initiated by magnetic reconnection.

No, YOU understate the importance of double layers and the circuit theory they necessitate.

You understate them on purpose because you don't want to put yourself out of a job.

 

[Reality Check]

This from a guy who thinks an object the size of an asteroid is spinning around at half the speed light, while being made entirely of neutrons, and it is ejecting a beam of light that is visible across galactic distances because the beam is being rotated directly at the earth like a lighthouse.

Logical fallacy of argument from incredibility.

Just because you cannot understand the physics of pulsars does not mean that they do not exist.
Off topic so start a new thread if you want to discuss it more fully michaelsuede. But in simple terms:

• Stars run out of fuel.
• That means that they collapse because it is the heat from the fusion in their center that makes then as big as they are.
  (unless you an an electric sky proponent in which case all stars have an internal temperature matching their surface and are the size of planets!)
• The collapse means that the force of gravity gets bigger. Eventually it gets so big that it squeezes electrons into atomic nuclei. Protons grab them to form neutrons. So you have a star made of neutrons.
• Conservation of angular momentum means that the neutron star sends up with a surface that is rotating much faster than before (think about the ice skater example taught to high school students).
  Some angular momentum is lost to matter blown off during the collapse.
  Some neutron stars with end up with surfaces with very high velocities, e.g. "half the speed of light".
• The magnetic field of the original star is intensified by being crushed into a smaller volume.

So now we have a small, dense rapidly rotating object with a high magnetic field. This generates electric fields. The electric fields accelerate electrons. Accelerated electrons emit radiation. This happens at the magnetic poles so beams of radiation are produced. If we see the beam then it blinks off and on just like a lighthouse beam.

 

[michaelsuede]

LOL

Ok

 

[Reality Check]

LOL

Ok

LOL

Thanks, Remember to post a link to the new thread here. The sceince behind pulsars is interesting.
Some of it is really basic (e.g. the internal heat source explaining the size of stars). But there is plenty of complex stuff.

 

[Dancing David]

I know you didn't just say that I'm the one who's falling into a trap with my understanding of theory.

This from a guy who thinks an object the size of an asteroid is spinning around at half the speed light, while being made entirely of neutrons, and it is ejecting a beam of light that is visible across galactic distances because the beam is being rotated directly at the earth like a lighthouse.

LOL

By the way, how are those double layers treating you guys in those MHD simulations you run?

Oh my...

um , so you reject the known physics because it doesn't match your internal reality. The fact that the forces that lead to the conclusion of neutron stars are measured and match the model is not a barrier for you... so which parts of the theory don't you accept?

Strong force, weak force, EM force and gravity.

Which is measured incorrectly and modeled incorrectly, what leads you to believe there are not neutron stars?

How does your theory explain the measured forces and model them correctly.

 

[Dancing David]

LOL

Ok

Some rejoinder, which force is modled incorrectly and measured incorrectly?

How does your model modfy and explain?

Why aren't there neutron stars?

 

[dafydd]

Yes, it can. And I've provided the relevant papers to show how it can. Stamping your feet and claiming it can't, when it clearly can, is ridiculous.



Very good! But if you acknowledge the existence of a DL as your source of anomalous resistivity, then why in the hell are you still spending my money on trying to solve the riddle of magnetic reconnection?

Could it be because MHD is completely incapable of modeling the mechanics of a DL? Could it be because you refuse to accept that the plasma parcels in question are part of a circuit and obey Kirchhoff's circuit laws as they do in the lab?



No, YOU understate the importance of double layers and the circuit theory they necessitate.

You understate them on purpose because you don't want to put yourself out of a job.

Where did you study this subject and what are your qualifications?

 

[dafydd]

I know you didn't just say that I'm the one who's falling into a trap with my understanding of theory.

This from a guy who thinks an object the size of an asteroid is spinning around at half the speed light, while being made entirely of neutrons, and it is ejecting a beam of light that is visible across galactic distances because the beam is being rotated directly at the earth like a lighthouse.

LOL

By the way, how are those double layers treating you guys in those MHD simulations you run?

Not just one guy. You are denying the existence of neutron stars. On what evidence do you base this extraordinary claim? Why would every astronomer and physicist in the world conspire to fake evidence of their existence?

 

[dafydd]

Oh my...

um , so you reject the known physics because it doesn't match your internal reality. The fact that the forces that lead to the conclusion of neutron stars are measured and match the model is not a barrier for you... so which parts of the theory don't you accept?

Strong force, weak force, EM force and gravity.

Which is measured incorrectly and modeled incorrectly, what leads you to believe there are not neutron stars?

How does your theory explain the measured forces and model them correctly.

Is it too much to expect the math a well? Or does our hero not believe in math,just like the other Michael.
Micheal2,what is your alternative explanation for this?

This image from 2001 explores the close bond between two neutron stars in the globular star cluster M15.

Chandra's image of a puzzling X-ray source in the globular star cluster M15 shows that it is not one neutron star binary system, but two neutron star binary systems that appear so close together (2.7 seconds of arc) that they were indistinguishable with previous X-ray telescopes.

In the 1970's astronomers discovered one neutron star binary system in M15, called 4U2127, with the Uhuru X-ray satellite. Subsequent data from X-ray telescopes indicated that the neutron star itself was not directly visible in X-ray light because it was hidden by an accretion disk of hot matter swirling from a companion star onto the neutron star. This picture was put into doubt when the Japanese Ginga X-ray satellite saw luminous X-ray bursts from the region in 1990. The length of the burst and other light characteristics implied that the surface of the neutron star was directly visible, in contradiction with earlier observations.

Chandra observations solved this mystery. The source could exhibit two contradictory modes of behavior because 4U2127 is not one source, but two: one whose neutron star is hidden by an accretion disk (on the left in the image), and one (right) where occasional X-ray outbursts reveal another neutron star's surface.

The broader implication of the Chandra discovery is that binary star systems with a neutron star orbiting a normal star may be common in globular clusters. Previously, and inexplicably, astronomers had never seen more than one of these neutron star binaries in any one globular cluster–a tight spherical region that can contain a million stars or more.

 

[Dancing David]

Rather than derail the thread, maybe we can take it here?
http://www.internationalskeptics.com/forums/showthread.php?p=7055564#post7055564

 

[Michael Mozina]

None of them do. However, Alfven's conditions are erroneous and therefore irrelevant.

Basically your *ENTIRE* argument seems to boil down to a belief that Alfven didn't have a clue what he was talking about. I'm sorry, I don't buy that claim, and you can't demonstrate it either. I've showed you papers from Mann and Onel, which you've never personally commented on that very nicely explain flares. Your whole claim is bogus Tim. Alfven was an 'expert' in his field of plasma physics, and even had a Nobel Prize to demonstrate that fact. He used circuit theory *CONSISTENTLY* in current carrying plasma. Please demonstrate your claim that it's doesn't properly apply to plasmas because Alfven isn't the only one that used it.

 

[Michael Mozina]

Absolutely false. No, circuit theory cannot, under any circumstances, ever describe the change in topology of the field.

Sure they can, it's called a transistor. In this case it's related to the movement of the circuit itself and a change in resistance (path of least resistance), but magnetic lines are completely and utterly incapable of 'disconnecting from' or "reconnecting to" any other magnetic line!

 

[GeeMack]

Basically your *ENTIRE* argument seems to boil down to a belief that Alfven didn't have a clue what he was talking about. I'm sorry, I don't buy that claim, and you can't demonstrate it either. I've showed you papers from Mann and Onel, which you've never personally commented on that very nicely explain flares. Your whole claim is bogus Tim. Alfven was an 'expert' in his field of plasma physics, and even had a Nobel Prize to demonstrate that fact. He used circuit theory *CONSISTENTLY* in current carrying plasma. Please demonstrate your claim that it's doesn't properly apply to plasmas because Alfven isn't the only one that used it.

Has there been no valid plasma physics research in the past 30 years?

Also, what is it about, "Those claiming there are problems with magnetic reconnection are responsible for demonstrating that to be true," is so difficult to understand? Maybe things are different now, but even when I was in grade school and high school science classes, that idea about who's responsible for the burden-of-proof was pretty standard stuff.

 

[Michael Mozina]

None of them do.

IMO that's the most telling statement of the thread. None of them satisfied his conditions, so they are *ALL* misleading and erroneous according to Alfven himself. In *ALL* current carrying scenarios, he used a *CIRCUIT* oriented approach. Onel and Mann's paper is another great example of a "circuit" oriented approach to plasma physics, which you claim doesn't even work! I'm sorry, but your whole belief system is evidently based upon the denial of the legitimacy of Alfven's *ENTIRE* work, and you've never even bothered to actually read it! Where's you Nobel in plasma physics Tim?

 

[Michael Mozina]

Has there been no valid plasma physics research in the past 30 years?

Is the Onel and Mann paper you keep avoiding like the plague less than 30 years old?

Also, what is it about, "Those claiming there are problems with magnetic reconnection are responsible for demonstrating that to be true," is so difficult to understand? Maybe things are different now, but even when I was in grade school and high school science classes, that idea about who's responsible for the burden-of-proof was pretty standard stuff.

I already did that for you. I showed you the criteria Alfven placed upon that concept, I showed you his Double Layer paper which explains how *HE* describes such events, and I've demonstrated that none of you have even bothered to read his work, let alone comment on it! Your whole belief system seems to be predicated upon *self imposed ignorance*. None of you will read Alfven's work, none of you comment much on it, and none of you have a clue what he said as a result of your complete lack of effort.

 

[GeeMack]

Sure they can, it's called a transistor. In this case it's related to the movement of the circuit itself and a change in resistance (path of least resistance), but magnetic lines are completely and utterly incapable of 'disconnecting from' or "reconnecting to" any other magnetic line!

Yet in thousands of words posted in this and other threads on this forum, plus literally millions of words posted on a variety of other science and skeptic themed forums on the 'net for nearly a decade, none of the people claiming there is some significant problem with magnetic reconnection has been able to support that claim objectively, scientifically, and quantitatively. Imagine that.