Linear Halbach Structures : The Influence of Different Arrangement and Dimensions on the Resulting Magnetic Field

The article presents the results of the experimental implementation of separate and opposing linear structures of different sizes using NdFeB permanent magnets. It focuses on the distribution of the resulting magnetic induction. For both separate and opposing structures, composed of two layers of magnets, the magnetic induction attained was much more affected by changes in the width of the central magnet than by the increasing width of side magnets. When the width of the central magnet in either of the two opposing double-layer Halbach structures was increased approximately three times, the area of the uniform magnetic field attained in the middle of a 20-mm-wide air gap was roughly three times bigger with only ca 7% lower induction in comparison with opposing Halbach structures of optimized dimensions. These make it possible to generate the maximum magnetic field in the middle of the air gap, but only in a narrow band.