[en] The electric field is a crucial parameter in theories of solar wind interaction with the magnetosphere. During the IMS this parameter has, for the first time, been directly measured in the interacting regions: outer magnetosphere, magnetopause, magnetosheath, bow shock and the adjacent solar wind. Among the first results are the verification of a large-scale dawn-to-dusk tangential electric field component at the magnetopause of typically 1 - 2 mV/m and a corresponding power dissipation of 50 Wkm^-2. The normal component of the electric field is typically of the same order of magnitude as the tangential component. Fine-structure features, possibly related to the entry of plasma, remain to be analyzed. (author)