Solar wind plasma entry observed by cluster in the high‐latitude magnetospheric lobes

Using the Cluster data during the period from January to April between 2001 and 2006, we find an observation of solar wind entry due to magnetic reconnection occurred in the terrestrial high‐latitude magnetospheric lobes, tailward of the cusps under northward interplanetary magnetic field (IMF). Occurrence rate of solar wind entry events in this study is of the same order as that for the Cluster orbital interval from August to October between the years of 2002 and 2004 as reported by Shi et al. (2013). In this paper, we further study the role of the IMF Bx and By components in the control of solar wind plasma entry based on the investigations of different magnetic dipole tilt variations between our database and Shi et al. (2013). This study shows that the asymmetry distribution of solar wind entry events in the northern and southern lobes could be caused by the variation of magnetic dipole tilt, which could influence the locations of the reconnection site on the high‐latitude lobe magnetopause. On the other hand, IMF Bx can also affect the solar wind plasma entry rate, which is also consistent with previous results. Therefore, we conclude that the “north‐south asymmetry” of solar wind entry events in the lobes could be the combined result of magnetic dipole tilt and IMF Bx. In addition, the IMF By component can influence the entry events in conjunction with the variation of IMF Bx component, which is in line with the Parker Spiral of the IMF. Key Points The solar wind entry rate into the lobes is the same order in different seasons The “north‐south asymmetry” of SW entry is caused by both magnetic dipole tilt and IMF Bx The IMF By (with Bx) affects event occurrence, as expected from Parker Spiral