Halbach permanent magnet
Halbach permanent magnet is a magnetic ring made from a specially arranged array of permanent magnets, capable of generating a strong one-sided magnetic field inside or outside of the ring, while there's almost no magnetic field on the other side. This design significantly improves magnetic field utilization efficiency and is widely used in high-performance magnetic devices such as particle accelerators, magnetic resonance imaging (MRI), and high-precision magnetic measurement equipment.