What is a Halbach Array Magnetic Assembly?
by Veronica Zuccarello
A Halbach array is a specialized magnetic assembly formed by permanent magnets that are arranged in such a way as to significantly increase the strength of the magnetic field on one side of the array while cancelling the magnetic field to nearly zero on the opposite side of the array. To achieve this, there must be a spatially rotating pattern of magnetization. This spatially rotating pattern of magnetization can be continued indefinitely, with the same effect repeatedly occurring throughout the pattern. Halbach array assemblies are beneficial because they are able to provide a highly controlled, high strength magnetic field.
Discovering the Halbach Array
The effect behind the Halbach array was first discovered by John C. Mallinson in 1973. He described “one-sided flux” structures as a “curiosity,” and he immediately saw the potential to apply this effect to technology such as magnetic tape. While Mallinson made the initial discovery, physicist Klaus Halbach took this effect to the next level during the 1980s. During his time studying at the Lawrence Berkley National Laboratory, Halbach independently invented the Halbach array with the intent of using the powerful magnetic force in particle accelerator beams, traveling wave tubes, and lasers. Halbach became a world leader in designing magnetic systems, and many machines came to depend on this innovative permanent magnet technology that bears his name today.
Halbach Arrays Today
Today, the Halbach array drives many components of modern technology that are essential to our everyday lives. Halbach cylinders, which are magnetized cylinders that produce an intense, contained magnetic field, are used in devices such as magnetic couplings, high field particle focusing cylinders, and brushless motors. In a simpler example, Halbach arrays can even be found in refrigerator magnets—the magnets stick strongly on one side, but don’t stick at all when you flip them over. This is the Halbach array in action—the magnetic field has been significantly increased on one side, while being significantly weakened on the other side.
At Bunting-DuBois, we utilize the power of the Halbach array in many of our custom magnetic assemblies. We frequently utilize Halbach cylinders as we produce rotors and magnetic couplings, among other custom assemblies. To learn more about custom magnetic assemblies from Bunting-DuBois, contact us today.