Time- and vector- resolved scanning Kerr microscopy had been performed on partially built hard disk writer yokes fabricated by Seagate Technology.Three Cartesian components of the dynamic magnetization were recorded simultaneously by a vector bridge detector.Dynamic images of the in-plane magnetization suggested an underlying closure domain equilibrium state.This state was found to be modified by application of a bias magnetic field and also during pulse cycling,leading to different magnetization rotation and relaxation behavior within the tip region.