The Equivalent Magnetization Current Method Applied to the Design of Gradient Coils for MRI

Hector Sanchez¹, Michael Poole¹, Feng Liu¹, Stuart Crozier¹

This paper presents an approach for designing gradient coils that is independent of the shape of the current-carrying surface. The approach employs the equivalency between a uniformly magnetized volume and a surface current density. A linear variation of the magnetization in each boundary element was assumed which is equivalent to a uniform current density. A suite of electromagnetic properties can be parameterised in terms of a thin, piecewise, linearly-magnetised shell; the magnetic flux density, stored energy, power, torque, force and eddy-current induced magnetic flux density were all considered. A QP optimization algorithm was employed to find the magnetisation distribution that satisfies the constraints of the electromagnetic design problem.