42 - 43 - 44

S.B. Karavashkin

Third, what specifically the Pointing vector is? Conventionally, this is the vector of flux of the EM field energy. To understand its meaning better, apply the derivation proving its existence. "The first important corollary following from the system of Maxwell equations is that the energy of EM field exists. To find the EM field energy, consider a closed system consisting of some field and particles. Find the work produced by the field forces upon the particles being within the volume  V . Taking the ratio of this work to the time unity and thinking the charges continually distributed in space, … , we can write as follows:

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The work of magnetic field force is zero, as this force is perpendicular to the velocity of particle.

Transform (12.1) with the help of Maxwell's equations. Expressing the density of current in terms of field vectors… , we yield

[1, p. 46].

We see that in the chain of equalities there was made a substitution

However we know from (12.1) that this density of current has appeared due to the charge velocity variation in the selected space under affection of the electric field strength. If following the logic of (34), this density of current (the charges shift velocity) is caused by the affection of curl of magnetic field and by the velocity of electric field variation. However from the expression used by the author himself -

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- we can easy yield other value of the density of current -

which is more plausible than (34), because it accounts the measure of inertia  m of the charge carrier. Furthermore, if  curl    and   /t  are the exciters of current within the selected continued space, then at least at the transition to the direct current the dependence

has to remain.

There is nothing new that the direct current with the density    excites the magnetic field in the surrounding space, but vice versa? Though, possibly, the drawback is not so much in (36) as in the shortage of experimental curiosity. I think, the authors of this substitution could be interesting in the following experiment.

Take the conductor 1 (see Fig. 4), insulate a part of its surface by the insulator 2, put on it the cylindrical grommet 3 of a material having large     and cover the entire construction with the solid housing 4 serving as a secondary path. If (36) was true, then with the direct current passing through the conductor 1, within the grommet 3 the solenoidal magnetic field will induce; in accordance with (36) it has to excite the electric current in the secondary path, and it can be registered on the busbars 5 and 6, since, as it is easy to see, all conditions of electrodynamics based on (36) have been satisfied, and the negative result (if such) can clear this issue surely.