Electromagnetic fields are modelled by four vector equations. The equations were put forward
by the physicist
James Clerk Maxwell
in the middle of the 19th century. Using
vector calculus ,
the equations can be written in a more concise form than originally
stated and they are listed below:
| (1) |
| (2) |
| (3) |
| (4) |
where the bold characters represent vector quantities:
E: the electric field vector in volts per metre,
D: the electric flux density vector in coulombs per square metre,
H: the magnetic field vector in amperes per metre,
B: the magnetic flux density vector in webers per square metre.
J: the electric conduction current density in amperes per square metre.
The scalar quantity r is the volume charge density in coulombs per cubic metre.
The equations simplify further for linear, isotropic non-dispersive materials.