Fig. 1.
(a–d) The density of O2+ ions near Mars on the noon-midnight meridian plane (y = 0) and (e–h) on the equator plane (z = 0). The Martian intrinsic dipolar magnetic field is (a, e) 0 nT, (b, f) 10 nT, (c, g) 30 nT and (d, h) 60 nT on the surface of Mars in the magnetic equator. The solar wind flows in the figures from left to right. In panels (a)–(d) the upper (z > 0) and the lower (z < 0) hemisphere is the North and the South hemisphere, respectively. In panels (e)–(h) the upper (y < 0) and the lower (y > 0) hemisphere are the dawn and dusk hemispheres, respectively. The red sphere has a radius of 3700 km (~1.09 RM).