Superconducting magnetic levitation: principle, materials, physics and models

Abstract

In contrast to the interaction between two magnets with opposite magnetization directions, the interaction between a permanent magnet and a superconductor can be stable and result in magnetic levitation. This property can be exploited for the development of high velocity rotating bearings with no mechanical contacts and for the development of levitated trains. In this review, we focus on this latter application. After a brief description of the other techniques developed for levitating trains and the resulting achievements, we describe the magnet-superconductor interaction and recall the achievements in this field. We then give insights into the properties of the employed magnets and arrangement of magnets and we detail the characteristics and the fabrication processes of the most frequently used superconductors. Focusing on physics, we detail the procedures generally used for measuring the vertical (levitation) and the lateral (guidance) forces in magnetic levitation and the results obtained from experiments. We detail and give a critical review of the various models proposed for reproducing the force measurements. In the conclusion we discuss the possible future developments of the technology.

Calculation of a magnetic force acting on small superconducting celestial bodies

“…A magnetic force is exerted on a superconductor when it interacts with the external magnetic fluxes. In terms of the experimental and numerical analysis, the most relevant data come from the investigations of magnetic levitation [23]. Significant differences were observed between field cooling (FC) and zero-field cooling (ZFC) conditions [24].…”

High Temperature Superconducting Non-insulation Closed-loop Coils for Electro-dynamic Suspension System

“…Based on EDS system's requirements, it is necessary to calculate the basic parameters of the HTS coils module and ground coils, including turns, magnetic momentum, and Geometric dimensions. The levitation and guidance load of EDS system depends on the linear motor stator (figure-eight-shaped coil) surface magnetic field and the total magnetic momentum of the magnets [2,18]. For achieving the levitation and guidance load, the total magnetic momentum of a single pole of an on-board HTS magnet needs to reach 360 kA, and the HTS coils module should be racetrack-shape.…”

“…There are three commonly used suspension technologies in high-speed maglev systems: electro-magnetic suspension (EMS), electro-dynamic suspension (EDS), and high temperature superconducting flux pining suspension [1][2][3][4][5][6]. EDS is generated from the electric repulsive force between the on-board magnets and the ground coils, and its suspension height can reach 50-100 mm.…”

High-Temperature Superconducting Non-Insulation Closed-Loop Coils for Electro-Dynamic Suspension System

“…There are three commonly used suspension technologies in high-speed maglev systems: electromagnetic suspension (EMS), EDS, and HTS flux-pinning suspension [1][2][3][4][5][6]. EMS uses the electromagnetic attraction between the on-board magnets and ground rails to create suspension, where the suspension height remains at 8 to 10 mm and a highly accurate control system is required.…”