3-D FEM analysis of residual magnetism produced by x-gradient coil of permanent magnet type of MRI

The detailed analysis of residual magnetization in permanent magnet type of magnetic resonance imaging (MRI) is important for the improvement of MRI image. The behavior of residual magnetization produced by the z-gradient coil is already reported. As 3-D analysis is strictly required for investigating the residual magnetization produced by the x- or y-gradient coil, the report about such a behavior is few. In this paper, the minor loop and residual magnetization produced by the x-gradient coil in a 3-D model are examined. The useful knowledge for understanding the behavior of the disturbance field due to the residual magnetization in the pole piece, etc., is obtained.