Finite element analysis of an array recording head

Classic analyses of recording head fields have been based on the Karlquist approximation, since it requires only knowledge of the gap edge and field point coordinates to find the field parallel to the gap (the orthogonal field is also known, although less often calculated). An older approximation, with this same convenience, was derived by Davy as the limiting form of a conformal mapping solution to the problem; interestingly enough, its error characteristics are roughly complementary to Karlquist´s. Thus, an average of these two provides a much improved estimate of the fields. This paper describes the proposed estimator and application of the finite element method for solution of nonlinear magnetic field problems in rectangular coordinates using vector potential formulation for an array recording head to validate the improved estimator.