What
happened to Electromagnetic Theory
On 21 April 1820, during a lecture, Řrsted noticed a compass needle deflected from magnetic
north when an electric current was nearby.
Faraday's breakthrough came when he wrapped
two insulated coils of wire around an iron ring, and found that, upon passing a
current through one coil, a momentary current was induced in the other coil.
This phenomenon is now known as mutual induction. Published in 1831. Or was it a current passed through one
coil, and what exactly was induced in
the other coil. Was it electric current? This question was not asked for the
next 200 years.
Faraday’s discovery closed the loop in an
elegant way. Electricity caused magnetism, which now caused electricity. But
did it?
Regarding Faraday, consider a single turn
transformer.
When the switch to the
battery off to the left is closed, a voltage/current step advances towards the
transformer at the speed of light, as below;
There are four factors which make up the wave ;
- electric current in the conductors i
- magnetic field, or flux, surrounding the conductors B
- electric charge on the surface of the conductors +q , -q
- electric field, or flux, in the vacuum terminating on the charge, D
Only
such complete ExH waves exist. It is impossible for
some of such a wave, for instance electric current i, to separate itself
from the rest, as was thought to happen in Faraday’s experiment when he
appeared to discover “electromagnetic induction”. The magnetism was present
along with the incident electric current. (This applies to Theory N and Theory
H. Under Theory C [now called “Theory
D” http://www.ivorcatt.co.uk/x8cbwash.htm
] , electric current is merely the mathematical manipulation of the edge of a
magnetic field, and so obviously cannot “exist” without its associated field.)
Reaching the transformer , some of it
continues on its journey at the reduced speed 1/√(µƐ) for the
magnetic material. Some of this transverse electromagnetic wave leaks out into
the secondary, continuing to travel at the 1/(√µƐ), as discussed in
my article in Electronics World in January 2011 . When the energy
reaches the right hand end of the transformer, some of
the TEM wave proceeds further to the right and some reflects. The TEM Wave
proceeding further to the right reached Faraday’s galvanometer, which could
only measure electric current and failed to detect the accompanying magnetic
field. At every stage, only TEM Waves, made up of electric and magnetic field,
were involved. At no stage was there isolated electricity or isolated
magnetism. Electricity did not cause magnetism did not
cause electricity. At every stage, a TEM Wave was involved, causing further TEM
waves.
In 1861 Maxwell enshrined the alleged
causal link between electricity and magnetism in Maxwell’s Equations. These are
taken to imply causality, but as my co-author Dr. David Walton points out, the
mathematics does not do so. It merely describes the relationship between E and
H in a TEM wave, which is one of fixed proportion. However, Maxwell obviously
thought causality was implied, because he proposed a crabwise process for
electromagnetic waves and light travelling though space, with changing E
causing Hand changing H causing E further away.
Maxwell’s Equations for a TEM Wave were
written;
δE/δx = - δB/δt
δH/δx = - δD/δt
They are taken to indicate causality. Not
surprisingly, the equally valid equation
δE/δx = -ZoƐo δE/δt ,
which I published in Electronics World in November
1985 as an Appendix , is overlooked. This last
equation tells us that E causes E! If E causes itself, does it really cause H
in the same way? See http://www.ivorcatt.co.uk/x4bp.pdf
.
When addressing a sinusoidal TEM wave
travelling at the speed of light guided by two conductors, a lecturer will tell
you that a changing E causes H, and a changing H causes E further along. No
text book or lecturer will tell you that E and H are in phase, and perhaps they
do not know it. Properly read, the first two formulae above tell you that
changing E correlates with changing
H. If one caused the other, we would expect to see something like
H = - δD/δt or + δD/δt
(displacement current causes magnetism),
but that is not what we see.
All lecturers and text book writers,
versed in the history of the subject, knowing of the discoveries of Oersted and
Faraday, “know” that E causes H, which causes E. This was fine for analogue
radio and even radar, when sine waves were the only signals, and there was
always a changing E and a changing H, so long as their relative phase was
unknown or ignored, as it was. However, along came digital electronics, where
the signal from one logic gate to the next was not a sine wave, but a steady
voltage of 0v suddenly changing to a steady voltage of 5v. While at 5v for some
time, a steady, constant flow of energy in the TEM wave involving fixed E and
fixed H travelled along the transmission line at the speed of light – and
perhaps could be classed as light.
According to Aristotle and today’s lecturers and text book writers, something
must still be helping the signal along. Since E and H were not changing, the
change in E could not be causing H and the change in H could not be causing E.
However, Fourier Series came to the rescue. Lecturers and text book writers
told each other that any (periodic) waveform could be represented by a
combination of sine waves, or possibly was
a combination of sine waves. (The word “periodic” was overlooked, since a step
is not periodic, and cannot be represented by sine waves.) Professor Archibald
Howie, while head of the Cavendish, went so far as to tell me that physical
reality was composed of sine waves! So in the middle of a steady signal, changing E and H caused
each other in one frequency component of the steady 5v signal, helping each
other along, while changing E could be causing H and changing H causing E in
another superposed sine wave! After all, it was known that in white light,
different colours (frequencies) could be superposed. The different colours must
be helping themselves along with their own varying E and H, ignoring the other
colours with their varying E and H,
sometimes varying in the opposite direction. So at the
same point, a rising E caused an H while a falling E caused an H in the
opposite direction.
The early discoveries of Řersted and Faraday, combined with the impression that
Maxwell’s Equations (above) imply causality, make the lecturer and text book
writer unable to envisage the correct version of the TEM Wave which I
attributed to Heaviside. I called it “The Heaviside Signal” Electronics World in July 1979 . This was admirably
described by Dr. David Walton in Electronics
World in November 1979
and November 1980;
I understand that Aristotelians believed
that a force was necessary to keep bodies in motion and that, in the absence of
this force, the motion would cease. This theory led them into certain difficulties.
For instance a spear, once thrown, appeared to
continue to move without a force being present. The philosophers rose to this
challenge magnificently with the theory that air, displaced from ahead of the
spear, rushed to the rear and generated the requisite force - the theory was
saved. Unfortunately they missed the simple point
first noted by Newton, that it is in the nature of a moving body to continue to
move.
In the same way I fear that Maxwell
invented a complex explanation for a very simple phenomenon, ie that electromagnetic radiation, or energy current [ExH], moves at the speed of light - and that's all, because
that is what energy current does. No mechanism invoking E producing H and H, in
return, producing E is required.
.... a faulty set of primitives can lead
to problems in a theory which necessitate the introduction of ad hoc causality
relations. In a similar way I believe that the causality relations alleged to
reside in Maxwell's equations (i.e. changing magnetic field producing electric
field and changing electric field producing magnetic field) are spurious. A
moving body continues to move because that is what moving bodies do; an
electromagnetic disturbance or energy current, of whatever distribution,
continues to move because that is what energy currents do. In other words the statement "energy current travels at the
velocity of light" is a primitive assumption in my theoretical framework
which requires no further explanation. In my framework the moving energy
current is the simple situation and 'static' electric and magnetic fields are
composite.
These ideas are unknown to any lecturer
or text book writer, and you will not find them published by any such. They are
at the core of a valid electromagnetic theory, which at present is stalled.
References are at http://www.ivorcatt.co.uk/x21.htm
Mike Gibson has worked out the
output waveforms resulting from various inputs to a one turn transformer.
Ivor
Catt February/October 2012
From: Ivor Catt [ivor@ivorcatt.com]
Sent: 15 November 2014 21:27
To: Christopher Spargo
Cc: Alex Yakovlev
Subject: SP? {Spam?} What happened to Electromagnetic Theory
Svetlana, Editor of Electronics World, sat on this
article and two more for
2 years. Still not published. [Still not published in 2020]
http://www.ivorcatt.co.uk/x7171.htm