Maxwell's theory and its features

Now almost every person knows that the electric and magnetic fields are directly interrelated with each other. Even there is a special branch of physics that studies electromagnetic phenomena. But even in the 19th century, until Maxwell's electromagnetic theory was formulated, everything was completely different. It was considered, for example, that electric fields are inherent only in particles and bodies possessing an electric charge, and magnetic properties are a completely different field of science.

In 1864, the famous British physicist DK Maxwell pointed to the direct interconnection of electrical and magnetic phenomena. The discovery was called "Maxwell's theory of the electromagnetic field." Thanks to her, it was possible to solve a number of unsolvable questions, from the electrodynamics point of view at the time.

Most high-profile discoveries are always based on the results of previous researches. Maxwell's theory is no exception. A distinctive feature is that Maxwell significantly expanded the results obtained by his predecessors. For example, he pointed out that in Faraday's experiment, not only a closed loop of conductive material, but consisting of any material, can be used. In this case, the circuit is an indicator of the vortex electric field, which affects not only the crystal lattice of metals. At such a point of view, when it is in the field of a dielectric material, it is more correct to talk about the polarization currents. They also do the work, which consists in heating the material to a certain temperature.

The first suspicion of the connection between electrical and magnetic phenomena appeared in 1819. H. Oersted noticed that if a compass is placed near a conductor with a current, the direction of the arrow deviates from the north pole.

In 1824, A. Ampere formulated the law of the interaction of conductors, later called "The Law of Ampere."

And, finally, in 1831, Faraday recorded the appearance of a current in a circuit in a changing magnetic field.

Maxwell's theory is designed to solve the basic problem of electrodynamics: with the known spatial distribution of electrical charges (currents), it is possible to determine certain characteristics of the generated magnetic and electric fields. This theory does not consider the mechanisms that underlie the phenomena taking place.

Maxwell's theory is designed for closely spaced charges, since in the system of equations it is considered that electromagnetic interactions occur at the speed of light, regardless of the medium. An important feature of the theory is the fact that on its basis such fields are considered that:

- are generated by relatively large currents and charges distributed in a large volume (many times larger than the size of an atom or molecule);

- variable magnetic and electric fields change faster than the period of processes inside the molecules;

- the distance between the calculated point of space and the source of the field exceeds the size of the atoms (molecules).

All this allows us to state that Maxwell's theory is applicable first of all to the phenomena of the macrocosm. Modern physics explains more and more processes from the point of view of quantum theory. In Maxwell's formulas, quantum manifestations are not taken into account. Nevertheless, the use of Maxwellian systems of equations makes it possible to successfully solve a certain range of problems. It is interesting that since the densities of electric currents and charges are taken into account, it is theoretically possible for them to exist, but of a magnetic nature. To this in 1831 Dirac indicated, having designated them as magnetic monopoles. In general, the basic postulates of the theory are as follows:

- the magnetic field is created by an alternating electric field;

- an alternating magnetic field generates an electric field of a vortex nature.