Resumen de Magnetic levitation of superconductors with translational symmetry
One of the most impressive and useful properties exhibited by superconductors is their ability to provide passive stable levitation in the presence of permanent magnets. With the discovery of high-temperature superconductors, which can show their unique features at liquid nitrogen temperatures, superconducting levitation has become a very active scientific and technological field after the important advances in theory, experiments, and even an incipient implementation of the technology in actual devices. In particular, there is an important recent interest in magnetic transportation and launching systems (Maglev systems) where bulk high-temperature superconductors allow the levitation of vehicles in permanent-magnet tracks, because of the good properties that have recently been achieved in melt-textured superconductors. In spite of their technological importance, a systematic theoretical framework that can describe the behavior of both levitation force and stability of this kind of systems with longitudinal symmetry does not exist. The aim of this thesis is filling this gap with this thesis. The main purpose of this work is to give some guidelines about how to obtain the best superconducting system possible with longitudinal symmetry, one having the largest values of the levitation force while being vertically and horizontally stable. In order to realized it, in this thesis we present a wide theoretical study of the magnetic forces and stability of levitating systems where a rectangular superconducting bar, which is immersed in a magnetic eld created by a guideway composed of different sets of rectangular permanent magnets, achieves levitation. Both the superconductor and permanent magnets are infinitely long in the same direction and have longitudinal symmetry.
