中文摘要：

当四颗簇卫星在 2001 年 7 月 22 日在 15 RE 附近在 magnetotail 正在旅行时，电子的强壮的排列地的沥青角度分发在高速度流动到达前就在 dipolarization 前面(DF ) 被观察。增加的电子流动仅仅在 DF 持续一个短时间时期，相应于就为 1 个 keV 电子的一些弹起的时期。这些电子贡献的排列地的电流同意很好，那在前面由四颗卫星由磁场观察计算了。这些电子溪流在 0.22 keV 的精力范围被发现，在 1 keV 附近的山峰。这些向下当前的电子可以被某些潜力在曙光区域附近发源，这被建议结构。这些电子的出现暗示 dipolarization 前面和联系排列地的电流的形成在联合的磁气圈电离层起一个重要作用。

英文摘要：

The strong field-aligned pitch angle distribution of electrons is observed right at the dipolarization front （DF） before the arriving of a high speed flow when the four Cluster satellites are traveling in the magnetotail around 15 RE on July 22, 2001. The increased electron fluxes only last for a short time period at the DF, corresponding to just a few bouncing periods for 1 keV electrons. The field-aligned current contributed by these electrons agrees well with that calculated by the magnetic field observations by four satellites at the front. These electron streams are found in the energy range of 0.2-2 keV, peak around 1 keV. It is suggested that these downward current electrons may be originated near the aurora region by some kinds of potential structure. The occurrence of these electrons implies that the formation of the dipolarization front and the associated field-aligned current play an important role in the magnetosphere-ionosphere coupling.