方形亥姆霍兹线圈磁场系统均匀性分析

方形亥姆霍兹线圈用于模拟零磁场或量程范围内的任意大小和方向的磁场,其磁场均匀区与线圈结构尺寸有关。为了得到其磁场均匀区与结构尺寸的关系,构建了方形亥姆霍兹线圈的数学模型,导出了线圈内部任意点的磁感应强度矢量表达式,得出了输出电流与产生磁场大小的对应关系,利用程控恒流源和磁强计跟踪补偿动态地模拟出稳恒磁场,对系统产生的磁场的均匀区进行了测定,分析表明,理论计算与实验结果有较好的一致性。

Analysis on magnetic field homogeneity of magnetic system based on square Helmholtz coils

The square Helmholtz coil is applied to simulate zero magnetic field or magnetic field in any size and any direction in the measuring range scope,its homogeneity is mainly affected by the coil′s structural dimensions.In order to obtain the relationship between uniform magnetic field area and coil dimension,the mathematical model of 3-D square Helmholtz coils was constructed,the vector formula of magnetic field distribution at any point in its internal was deduced and the corresponding expression between current and magnetic field intensity was obtained.It takes advantage of programming constant-current source and magnetometer to track compensation dynamically and simulate the static magnetic field,and it analyses the uniform magnetic field region,the results show that the theoretical and experimental results are in good agreement.