This paper presents results of a study that uses the output of a global MHD simulation to investigate the geometry and dynamics of solar wind deflection from tangential magnetic force acting at the magnetopause. Tangential magnetic force at the magnetopause is a consequence of merging between the geomagnetic field and the interplanetary magnetic field at the dayside magnetopause. This is the first study explicitly to show deflection of magnetosheath flow at the magnetopause and to compute deflection phenomenon quantitatively using self-consistent MHD. The presentation connects magnetopause deflection with polarcap magnetic perturbations called the Svalgaard-Mansurov effect. ¿ 2000 American Geophysical Union