Study of Numerical Method for Magnetic Shielding Problem Considering Actual Measurement of Magnetic Environment

A critical consideration in the optimal design of magnetically shielded rooms is the manner in which an external magnetic field, which should be shielded, is imposed on a target area. In this paper, we examined the possibility of applying the B_s method (the method of which the magnetic field B_s in the analyzed region is given) to the shielding problem with a measurement-based magnetic field, which includes an irrotational field component as noise, and, therefore, is inconsistent with Maxwell's equations. We show that the B_s method has a well-defined physical meaning for such an irrotational field component. Furthermore, we explain why the convergence and the accuracy of the B_s method are better than those of the A method.