The magnetosphere is the region of space that contains the geomagnetic field confined by the solar wind, which is the plasma flowing from the Sun at high speeds. Figure 1 depicts the structure of the magnetosphere. The magnetotail consists of open field lines in the tail lobe and closed field lines in the plasma sheet. As shown in Figure 1, open field lines are connected with the interplanetary magnetic field so that one end of the open field line is on Earth while the other end of the field line is in the solar wind. For the closed field line, both ends are anchored on Earth.