The magnetosphere formed in the interaction between the magnetized solar wind and the earth's magnetic field has a magnetopause that separates interplanetary and terrestrial plasmas. The self-closed magnetopause is covered by the solar wind streamlines that are closet to the earth. Solar wind streamlines that are closet to the earth. Solar wind streamlines are delineated by intersection curves of electric and magnetic equipotential surfaces. The front part of the magnetopquses is an electric equipotential surface that interfaces between oppositely directed interplanetary and closed field lines. The rear part is a magnetic equipotential surface that has open field lines passing through. Thus the magnetopause current is intense on the former closedness part of the magnetopause, which is a tangential discontinuity, and insignificant on the latter openness part, which is a rotational discontinuity. The part of closedness magnetopquse has a pair of T-type magnetic neutral points on the exterior/interior face of the current sheet. The part of openness magnetopause has an X-type magnetic neutral line, in the studied case of southward interplanetary field. The neutral line is manifested by its cross point in the noon-midnight plane in our tow-dimensional elucidation. In the noon-midnight plane, which is an electric equipotential surface, solar wind streamlines are delineated by traces of magnetic equipotential surfaces.