ELECTROMAGNETIC PINNING OF VORTICES BY NONSUPERCONDUCTING DEFECTS ANDTHEIR INFLUENCE ON SCREENING

An image method is developed in order to analyze the contribution of s creening currents to the interaction of vortices with cylindrical defe cts. In the case of layered superconductors the interaction between el ementary (pancake) vortices and a circular dielectric region is calcul ated. The method can be easily generalized to an arbitrary configurati on of vortices, and the deformation of the vortex lattice near a singl e defect is considered as an example. It also shows that the global ef fect of a collection of defects is to weaken screening of the magnetic field and renormalize the London penetration length for long-range fi eld components. More generally, the analogy between the London equatio ns at short distances and electrostatics is discussed in detail.