Figure 1: Solar wind entry regions in the high-latitude terrestrial magnetosphere as detected by Cluster.
From: Solar wind entry into the high-latitude terrestrial magnetosphere during geomagnetically quiet times
Entry regions are indicated here as red markers. The C1 orbits and magnetospheric field lines are projected into the Geocentric Solar Magnetospheric (GSM) coordinate system XZ plane to indicate locations. The magnetospheric field lines are plotted according to the T89 model8, and the magnetopause and bow shock are based on models by Sibeck et al.9 with a 2 nPa solar wind dynamic pressure. Background colours illustrate different regions of the magnetosphere and the solar wind. The dipole orientation (tilting towards the Sun) corresponds to 12:00UT on 3rd September 2002 and one complete orbit of Cluster for that day are plotted with a yellow line. Here we show a possible process of the plasma entry. When the IMF is northward, MR between the IMF and magnetic field in the magnetosphere may occur at the high-latitude magnetopause. As the dipole axis is tilted towards the Sun, IMF field lines (orange) with any Bx sign can interact with the magnetospheric field lines in the northern hemisphere (NH), whereas only those IMFs with positive Bx values (green) are more likely to interact with the magnetospheric field lines in the southern hemisphere (SH). This leads to different IMF behaviour for the events in the NH and SH, as shown in Fig. 4.
