GEM: Exploring the Relative Influence of Different Classes of Ion Outflow on the Coupled Dynamics of the Magnetosphere-Ionosphere-Thermosphere System

地球空间环境建模（GEM）计划解决磁层物理学中最关键的问题。这是一项重点研究，科学界根据其重要性和及时性选择主题。了解磁层的动力学需要对等离子体的来源有定量的了解。磁层的等离子体有两个主要来源：太阳风和电离层。为了了解太阳风、磁层和电离层系统，重要的是将这两种等离子体源都包括在整个系统的模型中。多年来，人们一直把重点放在太阳风上。这一建议将量化电离层的外流。在这项研究中的方法将使用耦合磁层电离层热层（CMIT）模拟系统，包括一个新的，灵活的极地风外流模块（IPW）。由此产生的模拟代码将通过社区协调建模中心提供给整个空间物理学界。1）哪类离子外流对磁层-电离层-热层耦合系统有最显著的影响; 2）离子流出对耦合MIT动力学的影响在多大程度上取决于产生离子流出的机制？ 将开发三个版本的极风模块：1）经典极风模型，2）极风的上边界条件由磁层模型设定的配置，从而允许离心力和压力梯度提供外流，以及3）包括由Alfvenic Poynting通量等输入调节的横向加速离子的启发式模型的配置。将通过计算这三种外流对极冠电位、Dst、半球外流率和半球功率以及磁层对流的质的变化的影响来评价这三种外流。

The Geospace Environment Modeling (GEM) program addresses the most critical problems in magnetospheric physics. It is focused research where the topics are selected by the scientific community based on their importance and timeliness. An understanding of dynamics of the magnetosphere requires a quantitative understanding of the sources of the plasma. There are two main sources of plasma for the magnetosphere: the solar wind and the ionosphere. In order to understand the solar wind, magnetosphere and ionosphere system it is important that both sources of plasma be included in models of the overall all system. Most emphasis over the years has been on the solar wind source. This proposal will quantify the outflow from the ionosphere. The approach in this study will be to use the Coupled Magnetosphere Ionosphere Thermosphere (CMIT) simulation system including a new, flexible polar wind outflow module (IPW). The resulting simulation code will be made available to the entire space physics community through the Community Coordinated Modeling Center (CCMC).This study will address two questions: 1) which classes of ion outflow have the most significant effects on the coupled magnetosphere-ionosphere-thermosphere (MIT) system and 2) to what extent do the effects of ion outflow on the coupled MIT dynamics depend on the mechanism producing the outflow? Three versions of the polar wind module will be developed: 1) a classical polar wind model, 2) a configuration where the upper boundary conditions on the polar wind are set by the magnetospheric model, thereby allowing centrifugal forces and pressure gradients to provide the outflow, and 3) a configuration which includes a heuristic model of transversely accelerated ions regulated by inputs like the Alfvenic Poynting flux. The three types of outflow will be evaluated by calculating their influences on the polar cap potential, Dst, hemispheric outflow rates and hemispheric power, and qualitative changes in the magnetospheric convection.