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**New Theories / Electromagnetic induction fundamentals **

« **on:**07/12/2008 18:37:50 »

**Electromagnetic induction fundamentals**

Background and actual explanation

The Maxwell equations and their predictions constitute the starting point for special theory of relativity.

Analyzing the interaction of a magnet and a conductor in frame of these equations, two different situations are observed: when magnet is at rest and conductor is moving and opposite, when conductor is moving and magnet is at rest.

For this elementary experiment a bar magnet, a coil and a galvanometer are necessary.

When there is no movement of the magnet bar relative to coil, or there is no magnetic field, there is no movement inside the galvanometer:

B = const. or B= 0 --> ∂B/∂t = 0 and finally E = 0.

When the bar magnet is moving (fig. 1), a variable magnetic field is generated (∂B/∂t ≠ 0).

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Figure 1.

This variable magnetic field, in turn, generates induced electric field according to the first Maxwell's equation:

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When bar magnet stands still and the coil is moving (fig. 2), there is no time variation of magnetic field and there is no induced electric field, according to Maxwell's equations:

B = Const. and ∂B/∂t = 0 and E = 0

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Figure 2

However, the galvanometer needle is equally moving left and right as in the precedent case.

The explanation of this asymmetry in actual physic is related to the transformation of electric and magnetic field in different reference systems.

An observer at rest relative to a conducting loop sees a changing flux of the magnetic field B as the magnet glides through the loop. According to Faraday’s law this movement induces an electric field E, which drives a current in the loop due to the electric force qE acting on particles of charge q.

But an observer at rest relative to the magnet sees the loop sweep with velocity v; now the magnetic force qv×B drives the current.

In this way special relativity connects the phenomenon of magnetism and electricity. Magnetism arises from the motion of charge. Different observers, in different inertial frames, will record different magnetic fields. In some cases, the magnetism may disappear in a given inertial frame. However, the total electro-magnetic force will still be the same for all observers.

Based on this consideration, actual physics should reconsider the Lorenz force as being at the same level of importance as any of the Maxwell equations and to include it as a sixths equation (the fifth regard the dependence of electric and magnetic characteristics on geometry).

**Why the actual explanation is wrong.**

I am not a fan of actual orthodox theory so it is time to analyze in detail the actual explanation and its correlation with experimental part.

It is quite complicate to enter into detail in case of a magnet moving, because the Faraday’s law does not have a basic explanation or a mechanism of electric field generation from a variable magnetic field. Of course in the book a simple and intuitive new explanation is offered for this law.

Therefore the discussion will be focused on the well known Lorenz force expressed as:

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The first inadvertencies regard the ,,nature” of Lorenz force. By comparison with electric force, the Lorenz force changes only the direction of a charged particle without any acceleration. Therefore, in principle, this force is not able to accelerate the electrons in a region of space and to establish an electron circulation in a closed circuit.

For the sake of discussion, this absurdity is leaved aside and the detailed electron-magnet interaction is presented.

Let’s consider a magnet bar as in fig 3. and let’s establish the direction of magnetic induction B in the magnetic field generated by magnet. Magnetic induction is a vector and is tangent all the time to the line field. As consequences, for any magnet, magnetic induction changes the sign, in the space around magnet, relative to N-S axe. For a region of space around north pole, B is directed to positive x, after that turns and is directed to negative x and finally, for a region close to south pole change again to positive x direction.

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Figure 3.

If the Lorenz force is correct, an electron with speed v, found in different positions with different orientation of magnetic induction B, will be acted on the same force as value, but with different orientations.

Considering a simple case of a rectangular loop, moving with speed v, directed to negative x direction, at beginning the direction of loop speed and magnetic induction are antiparallel like in fig. 4.

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Figure 4

In this condition the force acting over electrons is:

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When the magnetic induction change the sign, more precisely the magnet passes through the loop as in fig 5, the Lorenz force will be:

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When the magnetic induction change again the direction, in a position symmetric to initial case (fig. 6) again the Lorenz force is null.

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Figure 6.

Of course, even the greatest interaction is along the NS magnet direction it can be argued that B is not all the time parallel or antiparallel with v.

Let’s analyze this case too, so all possibilities of interactions are covered. In order to deduce the entire interaction over the loop is necessary to observe the symmetry of magnetic field produced by magnet as in fig. 7.

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Figure 7.

In the fig. 7, the interactions of electrons from two opposite parts of loop are figured. The angle between magnetic induction and direction of motion during loop movement cover all angle between 0 and 180 º. In fig. 7 a particular angle, let’s say 125º is figured.

When the formula for Lorenz force is applied, it can be observed that electrons in both part of the circuit are acted by equal forces. Therefore, due to the magnetic field symmetry, the electrons in ab and cd part of loop will run in the same direction (it is not important to establish in which direction).

The same reasoning can be made for the bc and ad part of loop.

When the general circulation of electron is counted at loop level it can be observed that simultaneously electrons are leaving the loop through both conductors, or another possibility: electrons are entering simultaneously through both conductors.

Maybe the experts in the vectors and electric current are so polite to present the ,,orthodox” explanation.