Electromagnetic Induction

As real effect in Nature a magnetic action of the atmospherics in form of magnetization of iron objects is known sufficiently long ago. For the first time these facts were observed and registered in sea-navigation in XVII century [1] as remagnetization of the ship compass needles and a magnetizing of steel objects under atmospheric lightnings and strokes. The electric character of lightnings was assumed already by Du Fay Ch. F. in 1737. Nevertheless, original Benjamin Franklin's experiments and observations on electricity [2] corroborates the identity of magnetic action of a lightning and other electric discharges, along with many other their common physical attributes and developments. So in experiments with "Leyden jars" in period untill 1751[2], B. Franklin established that a spark dischages of static electricity magnetized or changed polarity of magnetic poles of small iron objects (the sewing steel needles), which were in contact or near. Then later such experiments with "Leyden jar" were repeated in Italy by G. Beccaria (before 1758) with similar results. But in these experiments the magnetization had occasional character and the conclusive generality for dependence of polarity of magnetizing from sign of electrostatic charge and the direction of spark discharge was not established by him also as and distant character of induction electromagnetic action.
The arc discharge, discovered later by V. V. Petrov in 1802, as it is known, also have an electromagnetic effect, that for the first time was demonstrated experimentaly in 1821 by H. Davy (in conformity with proposal of D. F. J. Arago [4]) just after H. Ch. Oersted's discovery (1820) [3].

The fundamental discovery of H. Ch. Oersted (1820) [3] of ponderomotive magnetic action of direct "galvanic current" on magnetic compass needle for the first time gave a possibility for correct determination of direction of induction magnetic field that and was noted by Oersted hinself and A.-M. Ampere in clear form as "Rule of swimmer". Nevertheless, then in this 1820 the magnetization action on iron (sawdust) and steel by means of "galvanic (voltaic) current" for the first time was realized in experiments by D. F. J. Arago [4], in comparison with known magnetising action of "ordinary electricity" discharge (spark) [2], for both of which A.-M. Ampere proposed the common term - "electric current". The nature of origin of magnetic field of galvanic current in interpretation of H. Gh. Oersted (as "conflictus electrici"), as it is known, was wrong. The essential analogy is in nature and origin of magnetic field of conduction electric currents and convection electric currents. As it is known, M. Faradey had failure to bring out "phenomenon of electromagnetic induction" in direct experiment, in spite of the undertaken endeavours in this direction: his experiments of 1838 year to reveal a magnetic field of moving charged sphere were finished unsuccessfully. The similar experiments with moving charged spheres later in 1901 were performed by E. Adams (in J. J. Thomson's laboratory) with the doubtfull positive results. One of endeavours supply an explanation for origin of magnetic field of electric currents was nndertaken later by P. Langevin in 1912 - 1913 [11] in form of generalization of "Maxwell's displacement current law" on all varieties of electric currents (conduction current, convection current and displacement current).

The fact of excitation of magnetic field at change of electric field (in particular, a carry together with discrete charged particles in a conductor), which is known in no evident form from the times of Oersted's experiments (1820), received the further development in Maxwell's hypothesis of displacement currents (1862) [5] for the vacuum and for the substance media. Maxwell's hypothesis was verified indirectly by Hertz's discovery of electromagnetic waves (1888) and by the direct qualitative experiment of S. P. Thompson (1889) [10] with indication of curl magnetic field in the magnetic at change of electric field in the dielectric. The quantitative experiments of similar kind (for "transformation MMF") were carried out later (J. Br. Whitehead, 1903 - 1905; E. Koch, 1910). The further veryfication experiments for moving bodies were made with reference to a measurement of magnetic field of convection currents of a carry of free or bound electric charges [the experiments of H. A. Rowland (1876), W. C. Roentgen (1885) and A. A. Eichenwald (1901 - 1903)].

The phenomenon of "electromagnetic induction" [6], together with phenomena of "magnetic mutual induction" and "magnetic self induction", was identified in 1980 (A. M. Sidorovich [6, 7]) , as the dual symmetric induction phenomenon to classical fundamental phenomenon of Faraday's "magnetoelectric induction" (1831) [14]. The effect is essentially developed on the high frequencies for concentrated bodies or when the electromagnetic waves (H. Hertz, 1888) or magnetoelectric waves (A. M. Sidorovich, 1988) are propagating in the open space and in the waveguide directional or resonant systems.
"Electromagnetic Induction" (B. Franklin, 1751; J. C. Maxwell, 1862; A. M. Sidorovich, 1980), together with other fundamental phenomenon - "Magnetodynamic Force" (O. Heaviside, 1893; A. M. Sidorovich, V. A. Sichik, 1984), are the basis for principle of operation of "magnetic inductive machines" [13] with electric field of excitation (generators and motors, as well magnetic transformer with curl electric field), that opens ample scope for progress in the development of a number of another electrical and radio engineering devices and apparatus. Moreover, starting from New Conception of phenomenon electromagnetic induction, the cause of a beginning, configuration and polarity of original magnetic field of the Earth and the planets finds out an explanation in dependence of the speed and the direction it's rotation around own axis.
On practice a phenomenon of electromagnetic induction means, that a magnetic field and magnetization (magnetic polarization) should be produced by induction in any closed contour of a magnetic, when the electric induction flux across surface, bounded by this contour, is in change. It occurs in cases, when is a change of electric field itself or a motion of a magnetic through the external electric field, across it.
The quantitative representation of phenomenon of electromagnetic induction is in form of Law of Electromagnetic Induction. The produced MMF of electromagnetic induction in a contour is quantitatively equal and opposite in sign to the rate of change of electric induction flux (or electric flux linkage) across surface, bounded by this contour, and states in the form of "transformation MMF" and/or of "MMF of motion".

"Transformation MMF" (for contour of the one or a few turns of the magnetic, magnetodielectric or another magnetisable body in a changing electric field) state as following:

h = -(-/+)w dQ/dt = -(-/+)dYD/dt

where
h - the magnetomotive force (MMF), A;
w - the number of turns;
Q - the electric induction flux, C;
YD = wQ - the electric flux linkage, C.

Further, according to Lentz's Law (1833) [12], here the Rule of Lentz also is in force for determination of direction of induced MMF and exciting magnetic current of polarization in a contour, which always acts in such direction, that the produced by it the electric induction flux opposes the change in flux of electric induction, which produces the MMF. It, accordingly, demand for the opposite sign in the above presented relations, which in result may be both "-" and "+" (as it is above in equations), in dependence from accepted conditional directions.

As known, J. C. Maxwell has not worked out the equation for magnetomotive force, bounded with "a magnetizing action on an iron, moving in electric field", that was noted by L. Boltzmann in editorial comments to the German edition (1898) of J. C. Maxwell's works. Therefore, the results of above mentioned experiments for "MMF of motion" are quite adequate only to the generalized equations of Maxwell-Hertz for moving media (1890) [9] with modification of the formula of J. J. Thomson (1881) [8] for magnetic field of electric charges in translatory motion.

"MMF of motion" (in magnetic, magnetodielectric or another body, moving across an external electric field) state as following (in particular, for straightlinear part of body):

h = -(-/+)D l v
where
h - the magnetomotive force (MMF), A;
D - the electric induction, C/m2;
l -- the length of magnetic, magnetodielectric or another body, m;
v - the velocity of motion, m/s.

As a result, the direction of the induced MMF and magnetic polarization in magnetic, magnetodielectric or another body, moving in electric field across to the force lines, is determined by the mnemonic "rule of a left hand" or the strength induced magnetic field determined by the vector product (in agreed-upon rightwinding system of co-ordinates) [in the form of modification of the formula of J. J. Thomson (1881) [8], which originaly was introduced by him for expression of the magnetic field of a convection current]:
H = [D v]

LAW OF ELECTROMAGNETIC INDUCTION (J. C. Maxwell; 1862; A.M. Sidorovich, 1980) involves only the field components (in contrast to "Law of total electric current" or the first of equations of Maxwell-Heaviside) and in the integral form is thus as on Fig. 1.
The expanded expression of "Law of electromagnetic induction" in the differential form is on Fig. 2.
The term "electromagnetic induction", which has been unlegitimately using in period more one and a half century for Faraday's law of induction {contrary to Faraday's terminology for the opened by him phenomenon of "magnetoelectric induction" (1831)}, in new interpretation (1980), substantiated physically, terminologically and in a sense for another allied phenomenon, presents such natural fact, that a varying electric field - the cause, and a originated magnetic field - the consequence, namely, -- "Electromagnetic Induction" (Sidorovich A. M., 1980). Consequently, the dual symmetric induction phenomenon, in which a varying magnetic field - the cause, and a originated electric field - the consequence, is "Magnetoelectric Induction" (M. Faraday, 1831).

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LAW of ELECTROMAGNETIC INDUCTION (J. C. Maxwell, 1862; A. M. Sidorovich, 1980).
- Maxwell J. C. On Physical Lines of Force. Pt. 3 // Phil. Mag., 1862, vol. XXIII, p. 12 - 24.
- Sidorovich A. M., To binary-inversion interpretation of Maxwell's equations and the induction phenomena // News of Acad. Sci. BSSR. Ser. phys.-mat. sci., 1980, No 3, p. 126 (In Russian).
- Sidorovich A. M., Electromagnetic Induction (New Conception). -- Proc. Int. Symp. (ISEF'87), Pavia, Italy, September 1987, p. 25 - 27.
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In result, as the consequences of Law of Electromagnetic Induction, three new phenomena are as following:

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UNIPOLAR ELECTROMAGNETIC INDUCTION (A. M. Sidorovich, 1980 [6, 7]) [phenomenon]
http://www.squidoo.com/Unipolar_electromagnetic_induction
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MAGNETIC MUTUAL INDUCTION (A. M. Sidorovich, 1980 [6, 7])
[phenomenon]
http://www.squidoo.com/Magnetic_mutual_induction
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MAGNETIC SELF-INDUCTION (A. M. Sidorovich, 1980[6, 7])
[phenomenon]
http://www.squidoo.com/Magnetic_self-induction
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With such interpretation of the induction phenomena (notions, terms and essense) M. Faraday and J. C. Maxwell are also in solidarity, namely, also for phenomenon of "Magnetoelectric induction of Faraday" (1831) [14].
The phenomena "Magnetoelectric induction" (1831), "Electric mutual induction" (1831) and "Unipolar magnetoelectric induction" (1831) were discovered by M. Faraday actially simultaneously in 1831. As well the phenomenon "Electric self-induction" (J. Henry, 1832, M. Faraday, 1834 -1835) is special case of the phenomenon "Electric mutual induction" (M. Faraday, 1831) and the phenomenon "Magnetoelectric induction" (M. Faraday, 1831).
Similarly the phenomena "Magnetic self-induction" (A. M. Sidorovich, 1980), "Magnetic mutual induction" (A. M. Sidorovich, 1980) and "Unipolar electromagnetic induction" (A. M. Sidorovich, 1980) are the consequences of "Law of electromagnetic induction" (J. C. Maxwell, 1862, A. M. Sidorovich, 1980). and also the special cases of the phenomenon "Electromagnetic induction" (1751 - 1862 - 1980). Besides, the phenomenon "Magnetic self-induction" (A. M. Sidorovich, 1980) is special case of the phenomenon "Magnetic mutual induction" (A. M. Sidorovich, 1980) and the phenomenon "Electromagnetic induction" (B. Franklin, 1751; J. C. Maxwell, 1862; A. M. Sidorovich, 1980).

[1] Philosophical Transactions, 1676, vol. II, p. 309; 1732, vol. VIII, p. 25.
[2] Franklin B. Experiments and Observations on Electricity, 1770. [Benjamin Franklin's Experiments. - Cambridge, Massashusetts, 1941].
[3] Oersted H.Ch. Experimenta circa efficaciam conflictus electrici in acum magneticam. - Hafniae, 1820.
[4] Arago F., Annales de chimie et de physique, [2], 1820, t. XV, p. 93 -102.
[5] Maxwell J. C., On Physical Lines of Force. Pt. 3 // Phil. Mag., 1862, vol. XXIII, p. 12 24.
[6] Sidorovich A. M., Electromagnetic Induction (New Conception). - Proc. Int.
Symp. (ISEF'87), Pavia, Italy, September 1987, p. 25 - 27.
[7] Sidorovich A. M., To binary-inversion interpretation of Maxwell's equations and the induction phenomena // News of Acad. Sci. BSSR. Ser. phys.-mat. sci., 1980, No 3, p. 126 (In Russian).
[8] Thomson J. J., On the electric and magnetic effects produced by the motion of electrified bodies. - Phil. Mag., 1881, vol. 11, p. 229 - 249.
[9] Hertz H., Über die Grundgleichungen der Electrodynamik für bewegte Körper // Ann. d. Phys., 1890. T. 41. S. 369 - 399.
[10] Thompson S. P., On the magnetic action of displacement currents in a dielectric. - Proc. Roy. Soc., 1889, 45, p. 392 - 393.
[11] Langevin P., L'inertie de l'énergie et ses conséquences // J. de Physicue, t. 5, 1913, No 3, p. 553 - 591.
[12] Lentz E. Ch., Über die Bestimmung der Richtung der durch elektrodynamische Verteilung erregten galvanischen Ströme. - Ann. d. Phys. u. Chem., Leipzig, 1834, Bd. XXXI, S. 483 - 494.
[13] Sidorovich A. M., Comparison of the Principle Peculiarities of the Electric and Magnetic Inductive Machines. - Int. Conference on Electrical Machines, Istanbul (Turkey), 2 - 4 September 1998. - Proceedings of ICEM'98, vol. III, p. 1449 - 1454.
[14] Faraday M. Experimental Researches in Electricity [Ser.1, pt. 2. Evolution of electricity from magnetismus] // Philosoph. Trans. of the Royal Soc., 1832, p. 133 - 145.