Optimized and standardized circular-coil systems for homogeneous magnetic field generation

Abstract

Nowadays, there is a rising demand for the homogeneous magnetic field (HMF) as exposure resource for electrical immunity tests, biomedical experiments, etc. The design of the conventional HMF generators such as Helmholtz and Barker coils only focuses on the field homogeneity at the coil center, which leads to limitations in the available workspace of HMF. In this paper, based on a comprehensive definition of HMF, the optimized circular three-coil and four-coil systems were analyzed through an optimization method. By standardizing the coil parameters to the HMF parameters, it is easy to scale the coil systems for the desired HMF. In addition, two sets of concise formulae were presented as practical design tools. In comparison with the classic Barker coils, the proposed optimized coil systems enable a highlighted reduction in both total electrical power and conductor mass by 14.9% to 33.6%. Numerical simulations and experimental tests were presented to show the effectiveness of the theoretical results and the improvement in coil performances.

Fusion power supply advances by the J-TEXT engineering team

“…Its performance in generating the test field is better than the commonly used Helmholtz coil. Improved multi-coil configurations were also proposed [70,71]. As these improved coils are obtained from the line-current assumption, they are valid if the crosssection of the coil is small, and the field strength is only within several tens of mT.…”