Study on the Solar Wind-Magnetosphere Interaction Based on Remote Sensing Data From IMAGE Spacecraft

图像航天器上的低能中性原子成像仪(LENA)的观测表明，在高纬度磁鞘方向上的发射受到调制，使源在高纬度磁鞘中向赤道方向/极地移动。一个基于鞘磁通量分布和氢外游层数密度分布的模型解释了这些特征，这是由于磁层顶在尖端有凹痕运动的结果，提出了一种利用IMAGE/LENA监测尖点运动的方法。IMAGE/Lena和SuperDARN雷达的同时观测为这种方法提供了证据。对一次从IMAGE和POLAR同时观测的事件的详细分析表明，高纬度鞘发射由两部分组成：高纬度的稳定发射和断断续续发生的低纬发射，并且尖点离子的进入与低纬Lena发射的出现是同时发生的。这强烈地表明，Lena监测离子在尖端的进入以及尖端的压痕，并且尖端离子进入的显著通量发生在尖端压痕的赤道方向，并且与尖端压痕分开。Lena有时还观察到在极高纬度磁层顶方向的增强发射。IMAGE/LENA和SuperDARN雷达的同时观测表明，LENA发射与电离层反向对流向阳流动的增强同时出现。这表明Lena可以监测到尖点重新连接引起的离子进入，并且重新连接的位置以几分钟的时间尺度移动。在半径为8Re的球面上映射的重联“黑子”在波动的情况下，在10分钟内大约移动了1Re。

Observations by the Low Energy Neutral Atom (LENA) imager on the IMAGE spacecraft show that emission in the direction of the high-latitude magnetosheath is modulated in such a manner that the source shifts equatorward/poleward in the high-latitude sheath. A model based on the distributions of the sheath flux and of the number density of the hydrogen exosphere has explained these characteristics as a result of the motion of the magnetopause having an indentation at the cusp, suggesting a means for monitoring the cusp motion using IMAGE/LENA. Simultaneous observations from IMAGE/LENA and SuperDARN radar have given evidence for the means. Detailed analyses of an event of simultaneous observations from IMAGE and Polar have revealed that the high-latitude sheath emission consists of two parts : the stable emission at the higher-latitudes, and the lower-latitude emission that occurs on and off, and that that the entry of the cusp ions happens in concurrence with the appearance of the lower-latitude LENA emission. This strongly suggests that LENA monitors the entry of the ions in the cusp as well as the cusp indentation, and that the significant flux of the cusp ion entry occurs equatorward of, and separately from the cusp indentation. LENA also sometimes observes an enhanced emission in the direction of the very high-latitude magnetopause. Simultaneous observations from IMAGE/LENA and SuperDARN radar have shown that the LENA emission appears concurrently with the enhancement of the sunward flow of the reverse convection in the ionosphere. This shows that LENA can monitor the ion entry caused by cusp reconnection, and that the reconnection site moves on a time scale of several minutes. The reconnection "spot" mapped on a sphere having a radius of 8 Re shifts by approximately 1 Re over 10 minutes while fluctuating.