Changing or moving magnetic field

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Discussion Overview

The discussion centers around the nature of electromotive force (emf) in relation to changing or moving magnetic fields. Participants explore the conditions under which emf is generated, referencing Faraday's Law and the implications of moving magnetic fields in various contexts, including theoretical and experimental scenarios.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that induced emf is produced by changing magnetic flux, regardless of whether the magnetic field is moving or changing.
  • Others question the validity of emf generation if the magnetic field is moving but the flux density remains unchanged.
  • One participant emphasizes the importance of understanding Faraday's Law in this context.
  • Another participant discusses historical perspectives, referencing Einstein's work on the magnet/conductor problem and the implications for the Lorentz force equation.
  • Several participants argue against the notion that magnetic field lines can be said to "move," suggesting that this leads to incorrect calculations and misunderstandings of electromagnetic principles.
  • One participant shares articles that critique the concept of moving magnetic field lines and discusses the behavior of a rotating magnet and its effects on electric fields.
  • Participants speculate on the behavior of magnetic fields in superconducting rings and question whether the magnetic field would rotate with the ring.

Areas of Agreement / Disagreement

There is no consensus among participants regarding the nature of emf generation in relation to moving or changing magnetic fields. Multiple competing views remain, particularly concerning the interpretation of magnetic field movement and its implications for electromagnetic theory.

Contextual Notes

Participants express uncertainty about the implications of moving magnetic fields, the definitions of magnetic flux, and the conditions under which emf is generated. There are references to specific scenarios and theoretical frameworks that may not be universally accepted or understood.

Who May Find This Useful

This discussion may be of interest to those studying electromagnetism, physics students exploring the principles of electromagnetic induction, and researchers examining the theoretical implications of magnetic fields in various contexts.

  • #31
f95toli said:
...you can actually rotate the magnet my rotating the piece YBCO even if the latter is perfectly round; but this is ONLY due to the fact that the flux lines are pinned in the YBCO

You've really made me wish I had one of these in hand to play with. How far can the effect be taken? If you turn it 360 degrees that it won't turn 360 degrees back... will it? If you have several pieces like this, do they interact like ordinary magnets with one another? I'm daydreaming you could use this as an analog computer to solve complex "knots" in magnetic fields but I think that is simple misunderstanding. ;)
 
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  • #32
My two cents worth.

To my surprise, through experimentation, I have found that the "Flux tubes"/lines of force, do not move when the magnet is turned on its' axis but the field lines do move with the magnet when one flips it from N to S and/or back again. This would lead me to conclude that the N/S area are a property of the poles and not the magnet it self. Am I interpreting my visual confirmation correctly?

I've constructed a 3D magnifying glass, much like the iron fillings on a sheet of paper but in
3D (I'm not prepared to discribe the tool since I would like to put it on the market first) This tool shows clearly the findings above. Additionally I have found that lines of force can be shaped, meaning that they are able to be tightly spaced and as a result, finding stronger gauss readings, larger spacing give way to lower gauss readings. Can this be or are my readings awry?

And if I may pose one more question, or finding. In-order to shield magnetic influence, the mesh that is used will consist of weaves that intersect each other at right angles, effectively re-directing the flux along the plane of the mesh material or does it disapate the field and its' influence?
 

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