Magnetic properties of finite superconducting cylinders. I. Uniform applied field

TLDR

Finite superconductors exhibit demagnetizing effects that influence their magnetic properties, particularly for cylinders in a uniform applied field. The paper presents a model for calculating the magnetic levitation force of finite type‑II superconductors in the critical state. The model determines field and current distributions by minimizing magnetic energy in the superconductor, enabling calculation of the levitation force for finite type‑II cylinders under uniform or nonuniform applied fields. The model yields results for both constant and field‑dependent critical currents.

Abstract

A model for the calculation of the magnetic levitation force for finite type-II superconductors in the critical state is presented in a series of two papers. In the first paper, we describe the main features of the model and understand the effect of demagnetizing fields in the magnetic properties of finite superconductors by considering the case of a superconducting cylinder in the presence of a homogeneous applied field. Field and current profiles are calculated from a minimization of the magnetic energy in the superconductor after a change in the applied field. Results are presented for both constant and field-dependent critical currents. The procedure is general enough to be applied to the case of nonuniform applied fields, as long as the cylindrical geometry is preserved.