One of the major questions about magnetic reconnection is how specific solar wind and interplanetary magnetic field conditions influence where reconnection occurs at the Earth’s magnetopause. There are two reconnection scenarios discussed in the literature: a) anti-parallel reconnection and b) component reconnection. Early spacecraft observations were limited to the detection of accelerated ion beams in the magnetopause boundary layer to determine the general direction of the reconnection X-line location with respect to the spacecraft. An improved view of the reconnection location at the magnetopause evolved from ionospheric emissions observed by polar-orbiting imagers. These observations and the observations of accelerated ion beams revealed that both scenarios occur at the magnetopause. Improved methodology using the time-of-flight effect of precipitating ions in the cusp regions and the cutoff velocity of the precipitating and mirroring ion populations was used to pinpoint magnetopause reconnection locations for a wide range of solar wind conditions. The results from these methodologies have been used to construct an empirical reconnection X-line model known as the Maximum Magnetic Shear model. Since this model’s inception, several tests have confirmed its validity and have resulted in modifications to the model for certain solar wind conditions. This review article summarizes the observational evidence for the location of magnetic reconnection at the Earth’s magnetopause, emphasizing the properties and efficacy of the Maximum Magnetic Shear Model.

关于磁重联的主要问题之一是特定的太阳风和行星际磁场条件如何影响地球磁层顶重联发生的位置。文献中讨论了两种重新连接场景：a）反并行重新连接和b）组件重新连接。早期的航天器观测仅限于检测磁层顶边界层中的加速离子束，以确定重联 X 线位置相对于航天器的大致方向。磁层顶重新连接位置的改进视图是根据极轨成像仪观测到的电离层发射演变而来的。这些观察和加速离子束的观察表明，这两种情况都发生在磁层顶。利用尖点区域中沉淀离子的飞行时间效应以及沉淀和镜像离子群的截止速度的改进方法被用来在各种太阳风条件下精确定位磁层顶重联位置。这些方法的结果已用于构建经验重联 X 线模型，称为最大磁剪切模型。自该模型建立以来，多次测试已证实其有效性，并针对某些太阳风条件对该模型进行了修改。这篇评论文章总结了地球磁层顶磁重联位置的观测证据，强调了最大磁剪切模型的特性和功效。