Electromagnetic field
The unified field consisting of both the electric field E and the magnetic field B (equivalently, the antisymmetric tensor F^μν). Classical electromagnetism is the study of its dynamics. Full treatment across §07–§08.
Definition
This is a placeholder entry. The electromagnetic field is the unified object that combines the electric field E and the magnetic field B into a single physical entity. Classically it is described by Maxwell's four equations; relativistically it is described by the antisymmetric field tensor F^μν with components F^0i = E_i/c and F^ij = ε_ijk B_k. Under a Lorentz boost, E and B transform into each other — an electric field in one frame becomes partly magnetic in another, and vice versa. There is only one field; the E/B decomposition is frame-dependent.
The full treatment appears across §07 (gauge structure, the four equations, Poynting vector, stress tensor) and §08 (free-space propagation as electromagnetic waves). For the fully covariant tensor formulation, see §11 (EM & relativity).