A technique for resolution amplification in three-dimensional field calculations for recording heads

A technique for enhancing the detail and resolution of 3D finite element magnetic field calculations for recording heads has been developed. This approach (ZOOM) has proven useful for studying details of gap fringe fields for heads of arbitrary geometry. ZOOM involves performing a second finite element reduced scalar potential calculation within a rediscretized subvolume of particular interest using as boundary conditions the original FEM solution. Scalar potential values for new boundary mesh nodes are obtained by an appropriate interpolation scheme. ZOOM is often essential for recording head studies where the range of important linear dimensions can span three or four orders of magnitude. Discretization of such 3D structures to obtain high accuracy and detail in a single step is usually a practical impossibility. We have applied this technique to a study of side fringe fields of Winchester style heads with track side bevel angles of 45, 60, and 75 degrees. We report for the first time the computed side fringe field asymmetry arising from head structure asymmetry.