# Classical Electrodynamics

*The Great Soviet Encyclopedia*(1979). It might be outdated or ideologically biased.

## Electrodynamics, Classical

the classical (nonquantum) theory of the behavior of electromagnetic fields, which effects the interaction between electric charges. The fundamental laws of classical electrodynamics are formulated in Maxwell’s equations. The equations make it possible to determine the values of the basic characteristics of an electromagnetic field—the electric field strength E and magnetic flux density **B**—in a vacuum and in macroscopic bodies as a function of the distribution of electric charges and currents in space.

In classical electrodynamics the microscopic electromagnetic field generated by individual charged particles is defined by the Lorentz-Maxwell equations, which constitute the foundation of the classical statistical theory of electromagnetic processes in macroscopic bodies. The averaging of the Lorentz-Maxwell equations leads to Maxwell’s equations.

The laws of classical electrodynamics are inapplicable at high frequencies (at short electromagnetic wavelengths), that is, for processes that occur in small space-time intervals. In such cases the laws of quantum electrodynamics are valid.

G. IA. MIAKISHEV