Electromagnetic pinning of vortices by non-superconducting defects and their influence on screening

An image method is developed in order to analyze the contribution of screening currents to the interaction of vortices with cylindrical defects. In the case of layered superconductors the interaction between elementary (pancake) vortices and a circular dielectric region is calculated. The method can be easily generalized to an arbitrary configuration of vortices, and the deformation of the vortex lattice near a single defect is considered as an example. It also shows that the global effect of a collection of defects is to weaken screening of the magnetic field and renormalize the London penetration length for long-range field components. More generally, the analogy between the London equations at short distances and electrostatics is discussed in detail.