Having raised certain questions about a "model" for Electromagnetic
Induction in a Usenet thread, I received numerous "answers" pointing
to Maxwell's equations as the "model" and various establishment
"dogma" as the "explanation" of induction. The arguments that ensued
induced me to review the status and theory of Faraday Induction in the
light of some new investigations and a new look at Maxwell's equations
notably those musings by Oleg Jefimenko.
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First the following are the "accepted" rules and definitions in this
regard. Faraday Induction means the creation of induced currents
about a given current element. The magnitude and sign of the induced
currents depend upon the first derivative of the source current. The
direction of the induced currents is parallel to the source current.
It is also observed that a moving magnet or a wire moving in a
magnetic field also induces a current. The equation that describes
this is known as the Lorentz force equation. Therefore Faraday
Induction is believed to be related to TWO descriptions (See Feynman
quote in Wikipedia Induction article).
A second form of induction known as "Maxwellian Induction" where a
changing electric field creates a magnetic field is also believed to
exist. This is related to the fabled "displacement current".
These two forms of induction are believed to be the result of the
ability of a changing magnetic field to create an electric field and
of a changing electric field to create a Magnetic field. Furthermore
it is widely accepted that the E field of induction is basically the
same E field as in electrostatic attraction or Coulomb's law.
Therefore equations can be derived by freely substituting these E
fields at will.
This leads to the calculation of induction through the use of "Flux
linkages". The number of "flux lines" that pass through a given
surface and the rate of change of them therefore determines the
induced emf. In modern form we'd calculate the surface integral of
the changing magnetic field over the loop in which the induction is
induced.
Hence it is widely believed that this "model" explains Induction
effects.
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Unfortunately nearly all of the above ideas are utterly wrong.
Virtually ALL of the established explanations of Induction actually
make no sense whatever. Sorting it all out takes some work. Here are
the facts.
1. By reason of causality a changing electric field cannot create a
Magnetic field and a changing magnetic field cannot create an electric
field. In truth BOTH are created by a source current and once created
no longer interact with each other.
2. In spite of the nifty appearance of iron filings in a magnetic
field, "flux lines" is a bogus concept with no quantitative value.
Furthermore, 1 above proves that the use of the integral of a magnetic
field (Faraday's law) over a surface to find induced emf, while a
method that usually produces correct answers has no basis in the
physics of induction. The magnetic field cannot and does not "cause"
the E field of induction.
3. Maxwell induction and the displacement current have never been
demonstrated to exist and therefore have no experimental basis in
reality. Therefore we are reduced to having just Faraday Induction as
the ONLY form of induction.
4. Faraday induction exists only in non-moving systems and the Lorentz
force equation describes the case where things are in relative motion.
However it can be shown that the Lorentz forces are really just a case
of a transformation of reference frames from stationary to moving in
Faraday induction. It is the moving currents (charges) in moving
systems that create the induction fields. (See Jefimenko) Therefore,
non-moving Faraday induction is sufficient to describe ALL induction!
The Lorentz forces like "flux linkages" are merely mathematics that
give correct answers but have no REAL basis in the physics of the
situation.
5. Finally we must observe that the E field induced by changing
currents in Faraday Induction is NOT the same E field found in
electrostatic Coulomb attraction. It has different properties and
force directions. To blindly exchange these two E fields in equations
is clearly nonsense. A few researchers have made this point for a long
time.
6. We might also mention that the Vector Magnetic Potential, A, is
also non-causal to the induced emf of induction. This means that the
changing current to induced current effects of induction are operating
not through the intermediary of B or A and hence represent a current
to current mechanism that is NOT "explained".
The bottom line of all this is that the 'standard' Maxwellian
explanations and "model" of electromagnetic induction is completely in
error and any new "model" that might provide a "point of view" for the
current to current action of Faraday induction has not been
forthcoming. This therefore appears to be the current
"understanding" (or more exactly lack of it) of Electromagnetic
Induction and the physics that might lie behind it.
Let me thank all who responded to my recent thread. Even those who
responded with the wrong answers contributed because even arguing the
wrong things still causes one to rethink the whole issue to try to
prove what is "right" and what is "wrong". Hence the argument creates
the progress, while the various points made within it are merely
stepping stones to shaking out a better viewpoint! Thanks all.
