Mathematical Expression for the Magnetic Field of Single Polepiece Lenses

With the aid of the finite element method, an investigation has been carried out concerning the determination of mathematical expressions for the axial magnetic field distribution of zero bore single polepiece lenses with various pole geometries under the absence of magnetic saturation. Polepieces of flat and cuved tip have been considered under constant energising conditions. The computations have shown that different mathematical models would be needed to represent the lens magnetic flux density distribution with different shapes of the s Ingle polepiace. The results should be useful in predicting the optical parameters of the single polepiece lens by using the suitable expression for the axial magnetic field.