Magnetic Suspension and Propulsion Systems for High-Speed Transportation

High-speed transportation vehicles (trains) carrying superconducting magnets can be levitated by repulsion from diamagnetic currents induced in a conducting track. Various approximate methods are presented for calculating the lift and drag forces for such magnetic suspensions. Fourier analysis of periodic train magnet fields is used to analyze ``image-force'' and ``hybrid null-flux'' systems which involve homogeneous conducting sheet tracks. A lumped circuit analysis is used to discuss the ``null-flux'' principle and related systems with structured tracks. The stability and efficiency of linear induction and linear synchronous motor propulsion systems are studied using related methods.