Two Dual Formulations of the 3‐d Eddy‐currents Problem

Two variational formulations of the three‐dimensional eddy‐current problem are discussed and compared. One is based on the use of h (the magnetic field) and the associated magnetic potential as unknowns the other one is based on the use of a primitive of the electric field. They are found to be quite similar, suggesting some “duality” and, perhaps more importantly, that “mixed” finite elements, which were found efficient for the first case, could also be used for the second. This could alleviate some problems with the so‐called “modified vector potential approach” to the 3‐D eddy‐current problem.