Measurements of losses in a high-temperature superconductor exposed to both AC and DC magnetic fields and transport currents

摘要

In certain prospective applications of high-temperature superconductors the conductor will be exposed to both AC and DC magnetic fields and transport currents. It is therefore interesting to develop models, which can be based on measurements, of the losses under these conditions. In this paper we present an experimental study of the losses in a Bi-2223 high-temperature superconducting tape carrying transport currents in externally applied magnetic fields. Both the current and the magnetic field consist of an AC and a DC component. The losses were mainly measured calorimetrically, at a fixed temperature, for different combinations of currents and magnetic fields. In every single measurement, the magnitude of the magnetic field was directly proportional to the current, which is the normal case in most practical applications. The data obtained constitutes constitutes a good starting point for developing for developing a model of the losses.