GEM: The Role of Heavy Ion Outflow in Driving Sawtooth Oscillations

地球空间环境模拟方案是一个基础广泛、由社区发起的关于地球磁层物理以及磁层与大气和太阳风的耦合的研究方案。GEM的工作是通过一系列活动和焦点小组完成的，这些活动和重点小组解决具体问题，从而建立具有预测能力的全球地球空间环流模式(GGCM)。这个项目将有助于实现这一目标，即理解一种称为锯齿波振荡的基本而神秘的磁暴模式。特别是，该项目将调查从高层大气中逸出的重氧离子在这方面可能发挥的潜在作用。此外，该项目将支持一名研究生参与新汉普郡大学的研究工作。这项调查的具体目标是对FAST航天器在夜侧观察到的锯齿事件期间的离子流出进行叠加历元分析。这项研究将利用一个公开的数据库，其中包括122个锯齿事件，包括近500个单独的振荡，发生在FAST时代(1996年10月至2009年4月)。其中约三分之二覆盖了夜空极光。这构成了一个足够大的事件集，以允许比较锯齿事件(分别由SIR驱动和ICME驱动)的两个主要太阳风驱动因素，并能够将这些与非锯齿事件的流出进行比较。具体地说，FAST数据的叠加历元分析将被用来确定观察到的流出量是否在每颗“牙齿”之后增加，从而驱动下一颗牙齿。

The Geospace Environment Modeling (GEM) Program is a broad-based, community-initiated research program on the physics of the Earth's magnetosphere and the coupling of the magnetosphere to the atmosphere and to the solar wind. The work of GEM is accomplished in a series of campaigns and focus groups that solve specific problems leading to the construction of a global Geospace General Circulation Model (GGCM) with predictive capability. This project will contribute essential results to this goal pertaining to understanding a fundamental and mysterious mode of magnetic storms termed Sawtooth oscillations. Particularly, the project will investigate the potential role that heavy Oxygen ions escaping from the upper atmosphere may play in this. In addition, the project will support a graduate student participating in the research effort at University of New Hampshire. The specific goal of this investigation is to perform a superposed epoch analysis of ion outflow observed by the FAST spacecraft on the nightside during sawtooth events. The study will utilize a publicized database of 122 sawtooth events, comprising nearly 500 individual oscillations, which occurred during the FAST era (October 1996 to April 2009). About two thirds of these have coverage of the nightside aurora. This constitutes a sufficiently large set of events to allow for a comparison between the two main solar-wind drivers of Sawtooth events (SIR-driven and ICME-driven events, respectively) and to be able to compare these with the outflow from non-sawtooth events. Specifically, the superposed epoch analysis of the FAST data will be used to determine whether the observed outflow increases after each "tooth," driving the next tooth.