Design of Uniform Magnetic Field Coil With Off-Center Target Region Based on Slime Mold Algorithm for Atomic Magnetometers
Kang Yang, Yongle Zhang, Ahui Zhao, Hongwei Zhang, Qiannian Zhang, Daorong Rui, Xiang Wang, Dengchao Huang
Abstract
In this article, a modified design method is proposed for a kind of highly uniform magnetic field (UMF) coil whose target region is off-center defined. Combing the traditional target field method (TFM) with the slime mould algorithm (SMA), a new intelligent algorithm with excellent searching ability, optimal parameters can be obtained to determine the structure of the designed coil. To further improve the uniformity performance in the target region, a distance factor is introduced to optimize the distribution of target points. According to the simulation results from the finite element analysis, the absolute maximum uniformity error can be optimized from 0.098% to 0.060% if the SMA is utilized. And after the optimization of target points, the volume proportion of absolute uniformity error less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> can be increased to 64.60%. An up-scaled coil of 10 times is fabricated via the flexible printed circuit technology, and test results of the magnetic field generated by this coil show a good agreement with the simulation ones. It indicates that the actual uniformity error in the range of ±0.35R reaches to 0.11%, which is acceptable when taking manufacture and measurement errors into consideration.