Mass loading effects. The color on the y = 0 plane show (a) the Uz of newly ionized ion by e.g. photo ionization (X+), (b) the Uz of the solar wind H+ ions and (c) the magnitude of the magnetic field. The tubes in (a) and (b) show the flow lines of X+ and H+ ions, respectively. The color on the surface of the tubes shows the total ion velocity. The direction of the undisturbed solar wind vector (Usw = (−430, 0, 0) km s−1), the IMF vector (Bsw = (0, 5.88, 0) nT) and the convective electric field (Esw = − Usw × Bsw) are given on the left. Note that the bulk flow of X+ ions is toward the +Esw direction while H+ ions move toward the −Esw direction. Note also that X+ ions are produced in all places within the simulation box. The center of the X+ ion source is at the center of images at(x,y,z) = (0, 0, 0) and the unit of axes is 1,000 km.