Attractive levitation for high-speed ground transport with large guideway clearance and alternating-gradient stabilization

The author describes an attractive levitation concept that results in large guideways clearance and low magnetic drag and requires no feedback for stability. Dynamic stability is achieved by establishing alternating gradients of force in which the spatial dependence of the attractive force between the superconducting coils on the vehicle and the iron rails in the guideway is altered by periodic changes in the rail configuration. For a vehicular velocity of 500 km/h, the appropriate lengths for each configuration are in the range of 5 to 40 m, and the guideway clearance is in the range of 50 to 100 mm, depending on the details of the rail and vehicle magnet design