Solar wind dynamic pressure effect on the magnetic field topology in the southern hemisphere of the X–Z plane in the MSO coordinates under the northward and southward IMFs. The left, middle, and right panels stand for P_d = 1, 3, and 5 nPa, respectively; the upper and bottom panels represent the IMF conditions of B_Z = 3 and −3 nT. The arrows indicate the upstream IMF direction, the black lines with arrows represent the magnetic field lines, the red lines describe the separatrix angles of the magnetic reconnection configurations, and the color bars show the solar wind thermal pressure. The locations of the Martian MPB (the white dots) are identified by the same method of Fig. 3; the white lines are the MPB model results of Vignes et al. (2000).