八角形线圈的亥姆霍兹模式

Octagonal Magnetic Coils of Helmholtz Model

教科书中讲释亥姆霍兹线圈均以环形圈为模版。但在实际应用中,当需求规模较大尤其是建立三维体系时,为了便于定位,便于加工及节省材料,常采用正方形线圈为模版。不过线圈绕制中由于四个直角的应力作用,很难把握正方形线圈绕组的紧密和原型恆定、对称,显然这又有悖电磁学的诸多概念。鉴此,本文提出了以正方形为框架切去四角的八角形线圈模式,相应推出了满足亥姆霍兹线圈的基本条件,并给出了轴向磁感应强度的求解方程和均匀性的实测数据。

According to schoolbook,a Helmholtz model consists of two identical circular magnetic coils that are placed symmetrically one on each side of the experimental area along a common axis.However,square magnetic coils are actually used to be located and constructed easily and save materials when the model is big and a three-dimensional system is necessary.Unfortunately,it is difficult to insure the compactness,invariance and symmetry of the square coils because of the stress of four right-angles.As a result,octagonal magnetic coils are brought forward in this issue.It is based on the structure of square coils whose four right-angles are removed.It also accords with the basic Helmholtz model.It has deduced solving equations of axial magnetic induction intensity and measured data of homogeneity.