Figure 7: Schematic representation of the local, London, and Pippard limits in the parameter space given by the three length scales, the coherence length , the London penetration depth , and the mean free path . In the local regime is smaller than the distance over which the electric field changes, . When the superconductor is in the so-called dirty limit. The opposite situation is in which is the clean limit, in which nonlocal effects are important, and we have to consider Pippard's treatment. This regime can be subdivided if we also consider the third parameter . The case is the Pippard or anomalous regime, which is the regime of type I superconductors; is the London regime, the regime of the type II superconductors [46].