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

地球空间环境建模（GEM）项目是一个基础广泛、由社区发起的研究项目，研究地球磁层的物理特性以及磁层与大气和太阳风的耦合。GEM的工作是通过一系列运动和焦点小组来解决具体问题，从而构建具有预测能力的全球地球空间环流模型（GGCM）。这个项目将为这一目标提供必要的结果，这一目标与理解被称为锯齿振荡的磁暴的基本和神秘模式有关。特别是，该项目将调查从高层大气中逸出的重氧离子可能在其中发挥的潜在作用。此外，该项目将支持一名研究生参与新罕布什尔大学的研究工作。本研究的具体目标是对锯齿状事件期间FAST航天器在夜侧观测到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122个锯齿状事件数据库，包括近500个单独的振荡，这些振荡发生在FAST时代（1996年10月至2009年4月）。大约三分之二的卫星覆盖了夜侧极光。这构成了一个足够大的事件集，可以对锯齿状事件的两个主要太阳风驱动因素（分别是sir驱动和icme驱动事件）进行比较，并能够将它们与非锯齿状事件的流出进行比较。具体来说，FAST数据的叠加历元分析将用于确定观察到的流出是否在每个“牙齿”之后增加，从而驱动下一个牙齿。

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.