Author Topic: The possibility of non-Maxwellian E field during superconducting transition  (Read 1772 times)

Offline goran d

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If we switch a super-conductive disc between meissner and normal state by varying the strength of a magnetic field, something spins up the cooper pairs to produce the currents. We could assume that this is an E-field. This E-field is not according to Maxwell's Equations, since the charges are initially stationary and produce no field. This E-field moves in circles in the disc. So we could charge half the disc on one side positive, and the other half negative. And the extra-Maxwellian E-field produces force, not bound by Maxwell's Stress tensor. We can alter the charges on each side of the disc while switching the meissner effect on and off and produce a net force in one direction.

Offline Phil Stooke

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Ok... let us know when you get it working.

Online meberbs

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When running into something like this, your first reaction should be "maybe I don't understand this" not "I just overturned a field that has been studied in detail for over a century." https://xkcd.com/675/ (The mouseover text is especially relevant)

Conduction band electrons in a metal already are moving to begin with, so they don't need to be accelerated by an electric field, a magnetic field just bends their existing motion. (This starts at the superconducting transition in part because the lack of resistance means the electrons no longer are scattering off the nuclei and having their direction randomized.) Then a lot of complicated things happen as the patterns they move in cancel out the magnetic field inside the superconductor, and the changing magnetic field produces an electric field, plus forces between the electrons and the nuclei are relevant to some extent.

Online Stormbringer

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Aren't there 2 dimensional topological superconductors now which would constrain at least some of the chaos? maybe have two such things stacked upon each other or held close but separated by some space that could have the sort of orientation the OP was speculating about?
When antigravity is outlawed only outlaws will have antigravity.

Online meberbs

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The OP was talking about a violation of Maxwell's equations, and this isn't true. Without a violation of Maxwell's equations, the OP's idea won't go anywhere. (The main mistake was assuming conduction band electrons are stationary, I gave more detail than strictly necessary to point that out).

I haven't researched 2 dimensional superconductors (sounds interesting if I have time at some point) but if you are looking for a Maxwell's equations level derivation of how the currents initially form, it would still be difficult, because then you would need to account for the interactions with nuclei that generate the constraint, since Maxwell's equations don't reduce to 2D (cross products are inherently 3D).

Offline goran d

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I see more trouble for the idea that the magnetic field causes the charges to rotate. Since the force is the cross product of velocity and B field, the charges would have to shift outwards in order to be brought into rotation by the magnetic field. At first, this seems reasonable, as a gas with no resistance tends to expand, until it is stopped. (in our case by the electrostatic field). However, if we calculate the amount of distance that the charges would need to shift, and then find the static charge that would be accumulated due to the shift, it is enormous. The charges could not possibly shift by that much, it would create a breakdown in the surrounding air.

Online meberbs

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I see more trouble for the idea that the magnetic field causes the charges to rotate. Since the force is the cross product of velocity and B field, the charges would have to shift outwards in order to be brought into rotation by the magnetic field. At first, this seems reasonable, as a gas with no resistance tends to expand, until it is stopped. (in our case by the electrostatic field). However, if we calculate the amount of distance that the charges would need to shift, and then find the static charge that would be accumulated due to the shift, it is enormous. The charges could not possibly shift by that much, it would create a breakdown in the surrounding air.
Try sharing these calculation details, maybe giving an order of magnitude for what you are talking about, and what specific starting assumptions you have so I can show you why you are wrong. (Because it is really, really unlikely that you are right.)

I don't even know what you mean by "charges would have to shift outward." Do you mean the electrons would have to have some velocity component perpendicular to the magnetic field? The electrons are constantly moving in all directions, so the magnetic field will naturally curve the paths of any electrons not moving exactly parallel to the magnetic field (basically all of them). This is happening even before the superconducting transition.

The effects are known, expected, and observed. If you want to challenge part of this, you need to show the detailed work on why they shouldn't be the case.

Offline goran d

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The attached file is how I work out the shift.

Offline goran d

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The attached file is how I work out the shift.

Uh-oh, seems i have made the erroneous assumption that B is constant.

Online meberbs

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The attached file is how I work out the shift.

Uh-oh, seems i have made the erroneous assumption that B is constant.
Spatial and temporal variations in the B field are important in these calculations. (Especially temporal, as that generates E-fields).

Also, it slipped my mind entirely that the exclusion of an already present magnetic field is not expected of a perfect conductor. Superconductors have weird quantum effects that need to be accounted for that cause them to also act as a pefect diamegnet. In BCS theory, the electrons form Cooper pairs, allowing them to act as Bosons and form a Bose-Einstein condensate. I am not familiar enough with the details to explain why, but the quantum effects need to be accounted for on a macroscopic scale, which presumably means QED is required, not just pure Maxwell.

Also, for the high temperature superconductors, research is still ongoing to understand the mechanism, because quantum gets hard really quickly and the lattice structure of the ceramics in not trivial.

P.S. Looking at your original suggestion, it was to switch in an out of superconducting by varying the magnetic field, but this clearly generates an E-field by Maxwell's equations. I have been assuming that you are switching in and out by lowering the temperature which makes the question more interesting. Also worth looking up is Type II superconductors (which most high temperature ones are) since they have a range of magnetic field where they allow some penetration of magnetic fields that are strong enough but not too strong. This is not normal penetration as it is controlled by quantum mechanical vortices (again, I have not studied this thoroughly) and some interesting and useful effects result.

Offline goran d

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Some new considerations for the extra E-field:
I found out that the magnetization producing the same field for a sheet shaped object is much greater when the field is perpendicular to the sheet, than when it's parallel. And the volume is the same. That means if we switch off the meissner effect with parallel field, rotate the field till it's perpendicular, and then reduce until we switch on meissner effect, we should in theory get more energy than we lost. This is because the magnetic dipole moment is much greater.
If this were true it can be explained by extra fields. Or some short-lived magnetic monopole current, where only the fields pass through a discrete extra dimension for some time. The discrete dimension would have one value for monopole reality, and one for our reality.

Online meberbs

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Some new considerations for the extra E-field:
I found out that the magnetization producing the same field for a sheet shaped object is much greater when the field is perpendicular to the sheet, than when it's parallel. And the volume is the same. That means if we switch off the meissner effect with parallel field, rotate the field till it's perpendicular, and then reduce until we switch on meissner effect, we should in theory get more energy than we lost. This is because the magnetic dipole moment is much greater.
If this were true it can be explained by extra fields. Or some short-lived magnetic monopole current, where only the fields pass through a discrete extra dimension for some time. The discrete dimension would have one value for monopole reality, and one for our reality.
I am really not sure what you are trying to accomplish with what you said. Your conclusions really don't seem to follow from what you are saying. You made no supporting calculations at all, so I can't even point out where you made a mistake.

Offline goran d

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Here is a description of why magnetic moment is different and why energy is proportional to the magnetic dipole moment (for large loop of wire and magnetic moment near the centre).

Online meberbs

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That explained nothing.

'H "charge"' is simply not a term that has any meaning, therefore no sentence that includes that term has meaning. You also never defined M (Magnetic dipole moment? of what?)

The statement "integral of voltage with respect to time is proportional to the total magnetic dipole moment" does not follow from your previous statements at all. It may be a true statement if you defined your terms (what voltage?), defined the system you are describing (this would include explaining the time interval you are referring to, there are clearly systems and choices of time interval where this statement is utterly false), and then you could add in a few steps you skipped.

If you want to try again, I recommend using math, combined with clear variable definitions and a complete description of the system.