Magnetic reconnection and physical processes

[tusenfem]

What causes magnetic lines to "bundle" themselves into "tubes"? Are these tubes composed of something other than the carrier particles of the EM field?

That plasma flowing along the field line is called "current flow" and it is part of a larger "circuit" of energy. The "bundling" into a "tube" is directly related to that "current flow" process. It generates a magnetic field around itself and that magnetic field acts to constrict the flow of those moving charged particles into "tubes". It's called a "Birkeland Current".

Okay, so I did not say current, basically you agree with me about what twists the flux tube.

The flux tube can be chosen abitrarily actually, though often there are good reasons for what to chose, e.g. the sphere of Io for the Io flux tube or the loop that comes out of the photosphere. The MAIN loops are created NOT by the plasma that is in there (I asked brantc to calculate how much plasma is needed "circuling perpendicular to the field" to create said field, but he does not answer, gladly his mentor MM will probably answer this question) because the plasma flowing ALONG the core field of the flux tube CANNOT generate this core field, very very basic plasma physics, even Alfven and Peratt know that.

And it is not "Birkeland currents" it is "field aligned currents." Birkeland currents only occur in a planetary mangetosphere of a magnetized planet.

 

[The Man]

Which "physics", what "physics"?

The physics of, well, magnets and magnetic fields.

How does the movement together of two solid magnets due to magnetic attraction of their fields have anything to do with "magnetic reconnection" in plasma?

Who said anything about “in plasma”? In the case of the refrigerator magnets the magnets are not moving together “due to magnetic attraction of their fields” they are moving past each other by the force you apply in sliding them. As the magnetic fields reconnect you can feel that force required to slide them change . Magnetic reconnection is not restricted to within a highly conducive media like plasma.

Does anyone else even agree with you that what you're describing between two magnets coming together is actually a form of "magnetic reconnection"? Quick show of hands?

Again with the strawman MM, I have never claimed “two magnets coming together is actually a form of "magnetic reconnection". As to if the events I actually described involve magnetic reconnection, here are at least two who have expressed agreement.

If I move 2 bar magnets away from laying next to eachother and I look at what the field lines are doing (which is basically looking at what the magnetic field strength and direction is doing) I will find that first there are connections between the two in the first part and different connections between the two in the second part. Somehow these new connections were made, which is magnetic field line reconnection.

Naturally, because the magnetic field is a derivative, it would be better to look at reconnection in the vector potential, maybe michael can show us wrong in that view.

The magnetic field between TM's magnets is a reconnecting field, as you are welcome to discuss in the reconnection thread.

How many people agree with your description of the changes in the configurations of the magnetic fields. Oh that’s right you don’t have any and have claimed that it “is not "magnet*IC*”as you put it. So MM how many people agree with you that the interactions between the magnets as described is not, well, magnetic? No show of hands required.

 

[Michael Mozina]

Okay, so I did not say current, basically you agree with me about what twists the flux tube.

Current flow? How is that not "circuit" reconnection again if you have "current flow" lines changing their topology?

And it is not "Birkeland currents" it is "field aligned currents." Birkeland currents only occur in a planetary mangetosphere of a magnetized planet.

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. Such vortices can be seen in aurora as "auroral curls".[4]

 

[Michael Mozina]

Again with the strawman MM, I have never claimed “two magnets coming together is actually a form of "magnetic reconnection".

Fine, then we have nothing to discuss in this thread.

 

[The Man]

Fine, then we have nothing to discuss in this thread.

Unless you would actually like to discuss what I did assert instead of your strawman. If not then you simply have nothing to discuss in this thread.


Here it is again in case you’ve forgotten with the parts you seem to be deliberately ignoring bolded.

MM, take a couple of refrigerator magnets (the flat rectangular business card or credit card company types), they have alternating north south stripes (generally running vertically). If you place two back to back and slide them across each other you will feel those magnetic stripes alternately repelling and attracting each other. When you feel it switching from resisting the sliding to that sliding being easier (and being pulled in that direction) that is magnetic reconnection as field lines from the stripes on one refrigerator magnet reconnect to the next stripes on the other refrigerator magnet. No “magic magnets”, just what magnets do and reconnection that you can experience in your own kitchen or home. You could do the same thing with a compass and a magnet, the compass needle being itself a small magnet. When the magnet is far from the compass the needle is connected to the earths magnetic field as you bring the magnet closer to the compass at some point the felid of the needle reconnects to that of the magnet and the compass points at the magnet. Move the magnet away from the compass and the field of the needle will reconnect to the magnetic field of the earth. Repeat as many times as you feel necessary until you stop believing in "magic magnets".

So the reconnection is the switching from attractive to repulsive and back again in the refrigerator magnets and is the switching from the Earths magnetic field to the magnets magnetic field and back agian for the compass. If you are not interested in actually discussing magnetic reconnection or still assert that magnets are not magnetic then it is simply you that has nothing to discuss on this thread.

 

[Michael Mozina]

Dear TM,

Nobody doubts the existence of EM fields or that they have a physical influence on things. The debate about 'magnetic reconnection' is not related to your example of "magnet reconnection". My time is extremely limited this month, and I really don't want to dragged into a side conversation about magnetism in a general sense. I hear what you're saying, but it is completely unrelated to 'magnetic reconnection" in "plasma".

 

[The Man]

Dear TM,

Nobody doubts the existence of EM fields or that they have a physical influence on things.

Apparently you do since you claimed those reconnections are “not "magnet*IC*”.

The debate about 'magnetic reconnection' is not related to your example of "magnet reconnection".

As the examples given are of magnetic reconnections they are central to any debate about magnetic reconnection. Particularly where you insist magnetic reconnection must be the result of a misinterpretation of “circuit reconnection” or induction. Please show the “circuit reconnection” or induction in the examples of magnetic reconnection I have given.

My time is extremely limited this month, and I really don't want to dragged into a side conversation about magnetism in a general sense.

Then stop wasting your own time dragging around your strawmen.

I hear what you're saying, but it is completely unrelated to 'magnetic reconnection" in "plasma".

Apparently you do not as magnetic reconnection is not restricted to “in "plasma"“.

 

[Tim Thompson]

Magnetic Reconnection: Plasma or No Plasma?

The debate about 'magnetic reconnection' is not related to your example of "magnet reconnection". ... I hear what you're saying, but it is completely unrelated to 'magnetic reconnection" in "plasma".

Either magnetic reconnection is possible or it isn't. What does any plasma have to do with that, one way or the other? Or maybe you now think that magnetic reconnection is possible and perfectly ordinary & boring when there is no plasma, but impossible, silly & insane in the presence of a plasma? Have you finally gone completely insane?

 

[Zeuzzz]

Yawn.

"Reification (also known as hypostatisation, concretism, or the fallacy of misplaced concreteness) is a fallacy of ambiguity, when an abstraction (abstract belief or hypothetical construct) is treated as if it were a concrete, real event, or physical entity. In other words, it is the error of treating as a "real thing" something which is not a real thing, but merely an idea. For example: if the phrase "holds another's affection", is taken literally, affection would be reified."

 

[Reality Check]

Yawn.

"Reification (also known as hypostatisation, concretism, or the fallacy of misplaced concreteness) is a fallacy of ambiguity, when an abstraction (abstract belief or hypothetical construct) is treated as if it were a concrete, real event, or physical entity. In other words, it is the error of treating as a "real thing" something which is not a real thing, but merely an idea. For example: if the phrase "holds another's affection", is taken literally, affection would be reified."

Yawn.
The only person suggesting that that magnetic field lines are real physical thngs or being treated as real physical things, is you Zeuzzz.

FYI:
Field line

A field line is a locus that is defined by a vector field and a starting location within the field. Field lines are useful for visualizing vector fields, which are otherwise hard to depict. Note that, like longitude and latitude lines on a globe, or topographic lines on a topographic map, these lines are not physical lines that are actually present at certain locations; they are merely visualization tools.

Visualizing the magnetic field using field lines

 

[Zeuzzz]

Yawn.
The only person suggesting that that magnetic field lines are real physical thngs or being treated as real physical things, is you Zeuzzz.

Bzzzzt. Irony factor alert.

Magnetic field lines = physical

So, in magnetic reonnection, what are they exactly, if you'd like to clarify?

 

[The Man]

Either magnetic reconnection is possible or it isn't. What does any plasma have to do with that, one way or the other? Or maybe you now think that magnetic reconnection is possible and perfectly ordinary & boring when there is no plasma, but impossible, silly & insane in the presence of a plasma? Have you finally gone completely insane?

Well Tim he just wants to claim that "magnet reconnection" is possible, but somehow those magnets are simply just not magnetic. So his "magnet reconnection" is not magnetic reconnection (as his magnets apparently aren‘t magnetic). Insane certainly seems an appropriate description of what he is trying to assert.

 

[Zeuzzz]

No insane would be the person who is adamant something is happening right infront of them when holding magnets when infact nothing that effects physical reality at all is occuring.

One could say its a bit like a naked man wearing nothing but a moose head stood in the woods with a spade digging a huge hole and pointing out to any bystanders that now the levels dropped there is no longer an x marking that spot and that there seems to be 'lots of energy about da place', much to his amazement. Those contour lines are magic things you know.

 

[The Man]

Bzzzzt. Irony factor alert.




So, in magnetic reonnection, what are they exactly, if you'd like to clarify?

Same thing they are when not “in magnetic reonnection”, representations of the magnitude and direction of the field. Just like the vectors in a vector field, but you seem to have less of a problem considering vectors as representing something physical. Like say velocity, so please let us know if the next time you are traveling say 30 units of speed north you see a 30 unit length arrow extending from you pointing north.

 

[Zeuzzz]

physical. Like say velocity

Velocity is not physical.

 

[The Man]

No insane would be the person who is adamant something is happening right infront of them when holding magnets when infact nothing that effects physical reality at all is occuring.

One could say its a bit like a naked man wearing nothing but a moose head stood in the woods with a spade digging a huge hole and pointing out to any bystanders that now the levels dropped there is no longer an x marking that spot and that there seems to be 'lots of energy about da place', much to his amazement. Those contour lines are magic things you know.

Are vectors "magic things" too Zeuzz? Insane would also be considering one line or group of lines representing some physical properties as "magic", yet some other line or group of lines representing the very same physical properties is not.

 

[The Man]

Velocity is not physical.

So I guess you always stay in one place?

 

[Zeuzzz]

Thats not what I said. No velocity is not physical.

You can measure the velocity of something physical.

A velocity with nothing physical to prove said velocity 'exists' is just a made up number.

 

[The Man]

Thats not what I said. No velocity is not physical.

You can measure the velocity of something physical.

A velocity with nothing physical to prove said velocity 'exists' is just a made up number.

What you said simply makes absolutely no sense. Velocity is a physical property we can and do measure "of something physical" like say a particle or you and represent with a vector. A field is also something physical that we can measure and represent with field lines or vectors.


ETA:

Let’s consider a radio transmitter sending out a signal propagating at the speed of light. If we destroy or simply turn off that transmitter after one second are you claiming that signal (an electromagnetic field) no longer exists and can not be detected by a receiver one and a half light seconds away?

 

[DeiRenDopa]

Thats not what I said. No velocity is not physical.

You can measure the velocity of something physical.

A velocity with nothing physical to prove said velocity 'exists' is just a made up number.

What you said simply makes absolutely no sense. Velocity is a physical property we can and do measure "of something physical" like say a particle or you and represent with a vector. A field is also something physical that we can measure and represent with field lines or vectors.

Actually, I think what Z says makes a lot of sense ... he's just declared that one cannot do science, period.

Not only has he declared that the principle of induction - on which all of science rests - is invalid, but he has also declared all categorisations and abstractions to be invalid.

Apples, for instance, are not physical (only this particular apple, and that one).

Further, this thing (a specific apple, to the rest of us) has no relationship whatsoever to that thing (a different, specific, apple, to the rest of us); all there is is this thing and that thing (you can't even count them, since numbers are not valid).

It gets better (or worse).

We can't even have a discussion, because we have no way of associating anything either of us writes with anything the other writes.

Unless, of course, you'd like to explain to all readers just what you mean by "physical", Z?