GEM: Examination of Substorm Trigger and Development Mechanisms Based on Multisatellite Observations in the Near Earth Tail

在这个项目中，研究人员将利用多卫星观测来研究亚暴期间的尾流干扰。在亚暴爆发前，尾流破裂在释放储存在近地尾部的磁能方面起着重要作用。最近的观测表明，尾流破坏始于近地磁尾，然后沿方位和径向扩展，与电离层亚暴活动的扩展相对应。因此，尾流扰动的空间扩展是与亚暴相关的最基本的特征之一。该项目的主要目标是(1)找出尾流扰动的空间发展对尾磁构型的依赖关系，以及(2)找出触发(局部)尾流扰动开始所必需的磁条件。为了实现这些目标，研究人员将把重点放在早发的磁性条件上。将使用的数据包括：地球静止卫星和椭圆轨道卫星的磁场数据。磁特征将根据尾场构型和尾流强度的增强来解释。这项研究是第一次尝试从统计的角度来考察触发机制和电流中断的空间发展。对这种机制的理解是磁层物理学的主要目标之一。该项目的结果将对今后亚暴物理的理论和观测研究产生重要制约，并将有助于开展更多的全球研究，例如协调地面和卫星数据分析以及磁层亚暴的全球模拟。

In this project the investigators will study tail current disruption during substorms by making use of multisatellite observations. Tail current disruption plays an important role in releasing magnetic energy which has been stored in the near-Earth tail before a substorm onset. Recent observations have shown that tail current disruption initiates in the near-Earth magnetotail and then expands both azimuthally and radially, corresponding to the expansion of substorm activities at the ionosphere. Thus, the spatial expansion of tail current disruption is one of the most essential features associated with substorms. The main objectives of the project are (1) to find the dependence of the spatial developmental of tail current disruption on tail magnetic configurations, and (2) to find magnetic conditions that are necessary for triggering the (local) onsets of tail current disruption. To achieve these objectives the investigators will focus on preonset magnetic conditions . Data to be used include: magnetic field data from geostationary satellites and elliptically orbiting satellites. Magnetic signatures will be interpreted in terms of the tail field configuration and the enhancement in the tail current intensity. This study is the first attempt to statistically examine the mechanisms of the trigger and the spatial development of current disruption in terms of preonset magnetic configurations. The understanding of such mechanisms is one of the main goals of magnetospheric physics. The results of this project will put important constraints on future theoretical and observational studies of substorm physics, and will be useful as an input for more global studies, such as coordinated ground and satellite data analyses and global simulations of magnetospheric substorms.