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)计划解决了磁层物理中最关键的问题。这是一项重点研究，由科学界根据其重要性和及时性来选择主题。要了解磁层的动力学，就需要对等离子体的来源进行定量的了解。磁层有两个主要的等离子体来源：太阳风和电离层。为了了解太阳风、磁层和电离层系统，重要的是要将这两个等离子体源包括在整个ALL系统的模型中。多年来，最受重视的一直是太阳风源。这项提议将量化从电离层流出的流量。这项研究的方法将是使用耦合磁层电离层热层(CMIT)模拟系统，其中包括一个新的、灵活的极地风流出模块(IPW)。由此产生的模拟代码将通过社区协调建模中心(CCMC)提供给整个空间物理界。这项研究将解决两个问题：1)哪类离子外流对磁层-电离层-热层(MIT)耦合系统的影响最显著；2)离子外流对MIT耦合动力学的影响在多大程度上取决于产生外流的机制？极风模块将开发三个版本：1)经典极风模型，2)由磁层模型设置极风的上边界条件，从而允许离心力和气压梯度提供外流，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。通过计算它们对极冠位势、DST、半球流出速率和半球功率的影响以及磁层对流的质量变化来评估这三种类型的流出。

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.