Complex active control systems are not necessary for stable levitation.


Figure 1. A Basic Halbach Array consists of permanent magnets oriented in a sequence of quarter turns chosen to concentrate the magnetic field on one side. The motion of the array along a wire coil gives rise to an electromagnetic repulsion that can be exploited for levitation.

Figure 2. The Rotor in a Radial Halbach Magnetic Bearing has an outer layer consisting of a cylindrical version of the Halbach array of Figure 1. The bearing also includes multiple coils in a stator (omitted from this view) surrounding the rotor.

