An optimal method for 3-D eddy currents

A novel formulation for eddy current calculations in 3-D is derived.The method promises to require the minimum set of degrees of freedom, and also to be numerically Stable. A magnetic vector potential is used inside conducting regions, and it is shown that the gauge of this potential is implicit in the formulation. In non-conducting regions a magnetic scalar potential is used. The vector and scalar potentials are coupled on the interface between the two regions by the field continuity conditions, which implies zero current flow across the interface Computed results are compared with the analytic solutios of a conducting permeable sphere in an external field, and with measurements on a conducting block is a spatially varying field.