General solution of Maxwell’s equations is regarded here as a conversion of equation (1.33) to a classical textbook form of partial differential equations. So far, for this purpose the Lorenz’ gauge has been applied (e.g. Feynman, Griffiths). It is presented in this chapter that use of disadvantageous Lorenz’ gauge is not needed; simpler and better method can be applied. Equation (1.33) can be transformed using two methods, both yielding the same result. First method is to differentiate both sides of equation (1.33) with respect to time τ so we obtain: | |
(1.36) | |
and after changing the order of differentiation on the left side: | |
, | (1.37) |
then using value of calculated from (1.33) we have: | |
. | (1.38) |
Second method – calculating a curl of both sides of equation (1.33), we obtain: | |
(1.39) | |
and after changing the order of differentiation, this time on the right side: | |
, | (1.40) |
where we can use the value of ∇╳ P⃗ calculated from (1.33) so we have: | |
. | (1.41) |
In both cases we obtain: | |
(1.42) | |
Then use of value from (1.31) yields final formula: | |
, | (1.43) |
which can be considered as general solution of Maxwell’s equations, since it presents Maxwell’s equations
in a basic form of differential equations; on the left-side we have unknown function and its derivatives
and on the right-side forcing functions, in our case sources. . Equation (1.43) contains separated formulas for fields E and B, which is more transparent after expressing it in two separate equations – for real and imaginary parts: . | |
(1.44) | |
(1.45) | |
These two formulas are fully independent without additional limitations which
are imposed by using Lorenz’ gauge, and relate to the most general mathematical form of Maxwell’s equations,
i.e. including magnetic monopole and magnetic current. We can omit solutions for magnetic monopole and magnetic current sources, although such solutions can be easily derived from similar solutions obtained for electric field. The following equations then remain: | |
, | (1.46) |
. | (1.47) |
|