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What flows in magnetic circiut?

  1. Jul 3, 2012 #1
    In a electric current charge flows, what flows in a magnetic circuit?
     
  2. jcsd
  3. Jul 3, 2012 #2
    Flux.

    Claude
     
  4. Jul 3, 2012 #3
    Nothing flows, really. Well, if you have electromagnets, then current flows.

    Magnetic field lines are used to visualize the magnetic fields. In a magnetic circuit you try to see how the field lines behave, but usually in a snapshot, static manner.
     
  5. Jul 3, 2012 #4
    I am not certain that anything physical moves in the sense that charge moves in an electric current. There are no 'magnetic' charges or particles of any sort that flow.
     
  6. Jul 3, 2012 #5
    magnetic flux flows, and it is something physical and dynamic - just look at a reluctance motor. Just as charge is agitated in wires, magnetic dipoles are arranged in a magnetic core and resist or allow the flow of magnetic flux (see reluctance). Current flow is more than just the movement of electrons, its the propagation of the electromagnetic wave.
     
  7. Jul 3, 2012 #6
    See magnetic dipole, it is analogous to electric charge, although in most applications it would be fixed in position.
    http://en.wikipedia.org/wiki/Magnetic_dipole
     
    Last edited: Jul 3, 2012
  8. Jul 3, 2012 #7
    True to form Wikipedia is no help whatsoever: quote: ' the magnetic analogue of an electric charge has never been observed'
    Back to square 1
     
    Last edited: Jul 3, 2012
  9. Jul 3, 2012 #8

    Dale

    Staff: Mentor

    What is wrong with that? It is completely correct.

    If you have a problem with it then edit it.
     
  10. Jul 3, 2012 #9
    Does anyone have a text book reference (not a wikipedia reference please) relating to something flowing in magnetic flux?
     
  11. Jul 3, 2012 #10
    I don't have a text book reference but if it helps, an analogy for magnetic flux is electrical conductance and is proportional to the magnetic field (B) density in a given area ([itex]\phi[/itex]=BA - Magnetic flux = Magnetic field density * Area (when perpendicular)).

    So nothing actually 'flows' with magnetic flux, but the effects do in a way.

    Finally, here's a quote!

    "Magnetic flux

    A measure of the quantity of magnetism, being the total number of magnetic lines of force passing through a specified area in a magnetic field.

    The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company."
     
  12. Jul 3, 2012 #11
    An energy wave does indeed move. Although mag monopoles have never been discovered, mag dipoles have. It takes energy to align a dipole, which is what happens. Take a strip of magnetic recording tape. As the tape passes the recording head, the magnetic dipoles are aligned in response to the data signal. It takes work to do that, & the dipoles (domains) possess energy as a result.

    "Flux" does not imply an actual monopole discrete particle, but rather an energy wave or disturbance that successively re-orients a series of mag dipoles. Flux is real as long as we know what we are implying by the term.

    Claude
     
    Last edited: Jul 3, 2012
  13. Jul 4, 2012 #12
    As a good reference, I recommend Vol. 2 Ch. 13-16 of the Feynman lectures or J.D. Jackson's Classical Electrodynamics. Ch 5. deals with magnetostatics, Ch. 6 deals with magnetic flux.
     
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