Figure 4: IMF vectors for the events.
From: Solar wind entry into the high-latitude terrestrial magnetosphere during geomagnetically quiet times
(a) IMF vectors for the events that were observed in the northern hemisphere (59 events); (b) IMF vectors for the events that were observed in the southern hemisphere (45 events). Most events (84) occurred when the IMF was directed northerly, whereas only 20 events occurred when the IMF was southward, of which nine occurred during or within 10 min after the IMF turned from north to south, three occurred when the IMF turned within 1.5 h, and the rest occurred during time periods with an unstable IMF. The IMF Bx behaviour was very different for the events in the NH and SH, which can be well explained by the scenario illustrated in Fig. 1.
