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Why does a magnetic field remain stationary

  1. Feb 9, 2010 #1
    Why does a magnetic field remain stationary when rotated around its polar axis?
  2. jcsd
  3. Feb 10, 2010 #2


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    I don't follow your question. Is this in regards to a specific situation?
  4. Feb 10, 2010 #3
    If you mean "does a magnetic field rotate with a magnet that is rotated about it's axis" (as in say a Faraday unipolar generator with the magnets glued to the to rotating disk), the answer is that as far as I know it has never been established by experiment one way or the other which is true (rotates or not). In the case of a Faraday generator both cases give the same answer (for different reasons). However the question has been debated since the days of Faraday. A number of experiments have been proposed to make a determination (through the use of electrostatic measurements) but I've never seen a report where they were actually performed.
  5. Feb 10, 2010 #4

    Vanadium 50

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    A field is a number (or set of numbers) defined for each point in space. As such, it's difficult to even define what it means for a field to move.
  6. Feb 10, 2010 #5
  7. May 21, 2010 #6
    Maybe a rotating magnetic field produced the same affect on atoms as a stationary magnetic field. The affect could be like a shower head. It doesn't matter if the shower head is spinning or not, you still get wet. If that is true then we mayl never figure it out. Electrical machines such as transformers use an expanding and callapsing magnetic field to work. Generators and alternators use a rotating magnetic fields which produces expanding and collapsing magnetic fields in the stators. The Faraday Paradox relies on a different effect than expanding and callapsing magnetic fields. Work is force times distance. To have work something must move! In an AC transformer the magnetic lines of force are both the force and motion. In the homopolar generator the magnetic lines of force are only the force in the machine. Once the machine rotates you get the required motion which equals work. Since I don't know the correct answer all I can offer you is food for thought.
  8. May 22, 2010 #7
    This should be fairly easy to test.(I do not have magnets, so I can't)

    Anyway, obtain a disk magnet, such that the faces are the N/S poles.
    Then, obtain an iron disk of close to the same size.
    Separate the two with a thin sheet of smooth glass or whatever, such that the iron disk is attracted, but not too much.
    We all know that moving the magnet laterally will cause the iron disk to follow.

    So, instead of that, rotate the magnet. Does the iron disk rotate?
  9. May 22, 2010 #8
    In response to pallidin's message #7, the iron disk does not rotate. Now what?
  10. May 22, 2010 #9
    Then it is experimentally shown that the polar magnetic axis of a magnet does not rotate with a rotating magnet, else the iron disk would rotate.
  11. May 22, 2010 #10
    A search on papers by Jorge Guala-Valverde et al might provide some reports/experimental data.
  12. May 22, 2010 #11
    Why do you assume that a magnetic field is rigid and must rotate the iron disk? What if the magnetic fields of the poles actually rotate on their own? My problem is that the words I use don't have sufficient meaning. For example the term "magnetic field" describes something that nobody has seen. Sure it makes iron fillings behave a certain way, but it doesn't tell us what magnetic fields are. It seems to me that nothing of any real importance about magnetism has been discovered in the last 100 years. The creation of Neodium magnets only gives us a stronger magnet but no new understanding of magnetism. If there are new facts, I wasn't able to find them on the internet.
  13. May 22, 2010 #12
    NOT rotate the iron disk.
  14. May 23, 2010 #13
    By definition, electric and magnetic fields are attached to points in space, not objects. If you want a field defined to move with an object, it would be...a different field, and you could talk about the one that's attached to stuff like magnets.
  15. May 23, 2010 #14
    Look up Aharonov Bohm effect. See the figure with the electron beam and two slits in


    Bob S
  16. May 23, 2010 #15
    Bob S thanks for that link. (message #14) It was an excellent read, not that I fully understand it. It does however bring up Young's double slit experiment for more scrutiny. I've always believed that the results of Young's double slit experiment were interpreted incorrectly. I thought that the slits themselves caused the photons or electrons to deflect and show an interference pattern. When I say interference pattern I'm talking about what is observed on the view screen. The interference pattern might be a direct result of the particles interacting with the slit wall atoms. The solenoid in the Aharonov Bohm effect might be affecting the electrons in the slit walls and thereby affecting the interference pattern. The Aharonov Bohm effect could be detecting a new property of magnetism not previously observed. Or mabe the magnetic fields within the solenoid do spin and affect nutrinos which in turn affect the slit atoms.
    Anyhow to get back on topic; I believe that a magnetic field is not stationary. Therefore rotating a magnet around its polar axis will have no effect.
  17. May 24, 2010 #16


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    The Aharonov-Bohm effect does not make use of a double-slit experiment. It can be done with something as simple as a fiber optic cable that enters a splitter that routes the signal through two cables that go on either side of the solenoid and then join back into a single cable. The experimental setup is not too far removed from this. The experiment also is not detecting any new properties as it is fully explained by existing theorem at the time. The twist was simply that people did not think of a situation where the vector potential could affect a system in the absence of the magnetic field itself. However, quantum mechanics can do this because in quantum mechanics the scalar and vector potentials are the primitives, not the fields.

    As for your own interpetation of the double slit, I do not see that this being any different from the traditional intepretation. In the classical explaination, the waves diffract off of the edges of the slit. This can be seen more explicitly by widening the slit to sizes above a wavelength. This changes the result from an interference pattern to one mainly of diffractions.
  18. May 24, 2010 #17
    That, indeed, is the question.

    Edit: What bugs me is how simple this is to prove/disprove.
    Why hasn't it been done(by a reputable source)??

    Or perhaps it has and I'm just not aware of it(physics layman)
  19. May 26, 2010 #18
    Pallidin, that is a fair question. Why has this question not been definitively answered in the last 200+ years? I have spent more time trying to find reputable answers to this than I have spent actually working on experiment. Most of the proposed experiments are too overcomplicated or are unavailable with today's technology. Therefore, I approached the issue from a simpler view. Nature is simple, so the more complicated we try to make things, the less we learn, IMHO.

    Based on many experiments, Here is what i know right now.
    1) Under normal conditions, the magnetic field does NOT physically move with the body of the magnet itself.
    2) Unipolar generators (faraday disc generator) work because of similar affects as alternators, but under different conditions. It is widely believed that the UPG generates current based on Lorentz effect. However this may not be true at all.
    3) I have now entered into areas beyond any experiment that I have been able to find, and beyond my skill set (I need mathematical assistance) and need to recruit someone who can wrap their heads around these sets of experiments I've set up. Unfortunately, I don't even know where to begin finding a second party to verify the results and offer hypotheses and theories. I am in Portland, Oregon, if anyone is nearby and would like to take a look. Send me a private message if interested.

    Good Day,

    Last edited: May 26, 2010
  20. May 26, 2010 #19
    Agreed, that the standard definition of a "Field" when describing EM is a reference to points in space, rather than something physical, like a corn field.
    However, folks tend to think of a magnetic field as a physical thing, since it produces physical effects. And what if the magnetic "field" turns out to be a physical structure, that we just simply cannot directly observe? What would we call it? Perhaps the "Magnetic Flux Area" would be descriptive enough? Anyway, I've had to imagine the magnetic field as something physical in order to achieve what I have found to be something new, or at least something that I cannot find in exhaustive searches. Now that I can see this new method in action, it really has made me re-think what I have learned with regard to how and why electrical current is generated in alternators, transformers, unipolar generators etc.

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