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Electrostatic charge or dieletric field?

  1. Jul 28, 2014 #1
    Hi,

    I have a question on a quote I saw from Steinmetz regarding the two components of eletric field (magnetic and dielectric)

    To quote, ''Unfortunately, to a large extent in dealing with dielectric fields the prehistoric conception of the electro- static charge (electron) on the conductor still exists, and by its use destroys the analogy between the two components of the electric field, the magnetic and the dielectric, and makes the consideration of dielectric fields unnecessarily complicated.''

    Steinmetz continues, ''There is obviously no more sense in thinking of the capacity current as current which charges the conductor with a quantity of electricity, than there is of speaking of the inductance voltage as charging the conductor with a quantity of magnetism. But the latter conception, together with the notion of a quantity of magnetism, etc., has vanished since Faraday's representation of the magnetic field by lines of force."

    Steinmetz is considered a legend in electrical engineering, yet he references a "prehistoric" notion of charge on conductor. Why do we still use charges on conductors? What made us abandon the dielectric field? Why have we strayed from lines of force? Thanks.
     
  2. jcsd
  3. Jul 28, 2014 #2

    nsaspook

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    There has been progress in physics and engineering since Steinmetz.
    http://www.feynmanlectures.caltech.edu/I_02.html#Ch2-S2

     
    Last edited: Jul 28, 2014
  4. Jul 28, 2014 #3
    Yes, we photons are the carriers of electromagnetic phenomenon but this is defined by the perpendicular crossing of dieletric and magnetic field lines (transverse waves). Steinmetz was aware of the electrical phenomenon preceding electromagnetism as well.

    "At the present time no exceptions are found to the quantum-electrodynamic laws outside the nucleus, and there we do not know whether there is an exception because we simply do not know what is going on in the nucleus"

    A little confusing, no?
     
  5. Jul 28, 2014 #4

    Drakkith

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    I've never even heard of a dielectric field. It sounds like something used back before we knew what the EM field was. Since then, the electric field has been combined with the magnetic field to form the electromagnetic field. This combination is able to explain all classical electrical or magnetic phenomena.
     
  6. Jul 28, 2014 #5

    Born2bwire

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    Steinmetz is like Tesla and Edison era electromagnetic theory. Personally, Stratton and Chew are as far back as I'm willing to go for study material although Sommerfeld is interesting from a historical standpoint.

    I seem to recall that the dielectric field may be an older term for the polarization field.

    We've progressed leaps and bounds in electromagnetic theory since the first strong experimental results of Maxwell's theory in the 1880's. While the underlying theory has basically been complete since Maxwell put it down, there has been a lot of progress in simplifying and interpreting the theory. We just find better ways of representing the stuff. For example, Stratton uses Hertzian potentials but I much prefer the exponential potentials that Kong used in his work 30 years later. Both of them are correct, but I much prefer to work with the latter.
     
  7. Jul 28, 2014 #6
    The dieletric field is simply the electric field, and has similar field lines and electric flux just like the magnetic field. Except the electron has destroyed this analogy. The electron is just one end of the dieletric field....dielectric field is the same as magnetic field except magnetic fields form circles around wire while dieletric lines shoot out radially from a conductor
     
  8. Jul 28, 2014 #7

    Drakkith

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    Okay. So your question is why we abandoned the dielectric field? Because modern EM theory works using the electromagnetic field and explains practically all observed phenomena better than alternatives.
     
  9. Jul 28, 2014 #8

    Born2bwire

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    Saying that the dielectric field has similar field lines as the magnetic field only increases my suspicions that the dielectric field is an analogy of the Polarization field. Electric charges are monopoles while all magnetic fields are produced by at least a dipole. The Polarization field is the result of the the induced dipole moments in a dielectric due to an applied electric field. So the lowest multipole represented in the Polarization field is the dipole, like the magnetic field.

    Perhaps the concept of dielectric, bound charges, and its polarization were not well known, developed or understood when Steinmetz made his statements. That would account for his frustration at a complex theory for dielectric fields. For example, Debye relaxation was posed around 1910 I think.
     
  10. Jul 28, 2014 #9
    Steinmetz had an excellent grasp of electromagnetic and eletrical phenomenon. He invent complex versor algebra to describe AC phenomenon and was. What eminates out of a charge? An E-field...
    Dielectric-and-Magnetic-Flux-Lines-2.png

    This picture is familiar, applies to all conductors and explains the dieletric/magnetic field directions and their orthogonality.
     
  11. Jul 28, 2014 #10

    Born2bwire

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    Then what do you purport to be the difference between the dielectric and the electric field?
     
  12. Jul 28, 2014 #11
    Well, for one an electric field is thought only to exist after a charge exists and propagates with c. Second, dieletric fields must end on conductors or themselves, electric fields do not need to end on conductors, but can formed closed loops.

    It mostly is semantics, they represent the same idea but the electric field is more difficult to understand because of how it ties in the electrical charge, electron. As steinmetz said, there is no more sense in thinking that current charges a space with an amount of magnetism as there is of conduction current or voltage charge a plate with a certain amount of electrification, as described above.
     
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