The Halbach Array permanent magnet is a magnetic structure that is nearly ideal for producing the strongest magnetic field with a minimum number of magnets. In 1979, American scholar Klaus Halbach discovered this special permanent magnet structure during electron acceleration experiments, and gradually perfected this structure, eventually forming the so-called “Halbach” magnet.
The Halbach magnetic ring combines the radial and parallel arrangement of the magnets. If the end effect is neglected and the permeability of the surrounding magnetic material is regarded as infinity, the above permanent magnet structure eventually forms a unilateral magnetic field.
Different array modes can form different combinations of magnetic rings: