Superconductivity
High critical temperature superconductors - Physics and applications

The electromagnetic properties of materials are governed by Maxwell's equations, which relate the electromagnetic field to the electric charges and currents present. They can be written locally (at each point in space) or globally (integrated over a region of space). Consider a volume distribution of fixed electric charges ρ _q (r) and a current density j(r) in a region of space, where r is the space coordinate vector. This set of fixed and moving charges generates an electric field E(r) and a magnetic field B(r) (to be exact, a magnetic induction) at every point in space.

The local Maxwell equations are then written :