Abstract:  A typical problem related to magnetic medium is to calculate the magnetic field distribution in a uniformly magnetized sphere, that is, to solve the distribution of magnetic induction B in a sphere with radius R and uniform magnetization M in the space. If the surface or volume of the sphere is taken as a microelement, it will be difficult to analytically solve the expression of the magnetic field and the upper and lower limit of the integral at a point in the sphere, but the traditional method for solving the magnetic charge often lacks a strict demonstration of the equivalence of the magnetic charge. Therefore, in this paper, under the viewpoint of current element in accordance with the essence of physics, an equivalent solution to this problem is proposed by using the idea of cut-complement and equivalent substitution, which has a good enlightening effect and reference value for the relevant teaching and research of electromagnetics.

Key words: magnetic medium, current element, magnetic induction intensity, equivalent substitution