GEM: Impact of Coupling and Feedback Processes in Geospace on Ring Current Dynamics

GEM：地球空间中的耦合和反馈过程对环流动力学的影响

• 批准号: 0402163
• 负责人: Janet Kozyra
• 金额: $ 29.8万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-15 至 2007-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0402163&HistoricalAwards=false
• 关键词: GEM; Impact; Coupling; Feedback; Processes

The dynamics of the ring current is the predominant source of the magnetic variations that produce a magnetic storm. It is clear from observations over the last solar cycle that ring current dynamics during magnetic storms couples strongly to other regions of geospace. This project will combine models and observations to uncover the linkages and feedbacks between the ring current and these other regions. Two influential factors will be investigated as part of the proposed effort:(1) inner magnetospheric ion precipitation zones and their relation to stretched magnetic configurations, and (2) global sawtooth oscillations and their impact on the ring current. A set of magnetic storms has been selected for detailed comparative analysis during this research project. For each focus topic, it is expected to achieve: (1) clarification of the nature of the selected coupling and feedback mechanism; (2) advancement of our knowledge of geospace as a complex natural system; and (3) improvement of our ability to simulate the magnetospheric system on a global scale. The analysis will employ two codes developed at the University of Michigan. The first is the Ring Current Atmosphere Interaction Model (RAM), which now includes a self-consistent electric field model. The second is the Comprehensive Space Environment Model (CSEM), which now includes two-way coupling between the magnetohydrodynamic (MHD) simulation code and the kinetic Rice Convection Model (RCM), improving the accuracy of the inner magnetospheric results. Data sets used to constrain, validate, and/or drive the simulations include: particle observations on the geosynchronous Los Alamos National Laboratory (LANL) satellites; ion precipitation from National Oceanic and Atmospheric Administration/Polar Operational Environmental Satellites (NOAA/POES); thermal plasma observations and polar cap potential from the Defense Meteorological Satellite Program (DMSP) satellites; Energetic Neutral Atom (ENA) images from Imager for Magnetopause-to-Aurora Global Exploration/High Energy Neutral Atom (IMAGE/HENA) and Medium-Energy Neutral Atom (MENA) instruments; plasmasphere observations from IMAGE/EUV (Extreme Ultraviolet Imager); magnetic field observations from Geostationary Operational Environmental Satellites (GOES); and ground-based magnetometer data. The study will be the basis for a graduate student's Ph.D. dissertation. Study results will improve scientific understanding of a number of unanswered magnetic storm questions and the results will be made public through presentations and publications. The project will benefit society by improving scientific understanding of some important physical processes responsible for space weather effects, such as Global Positioning System (GPS) errors and satellite anomalies.

环电流的动力学是产生磁暴的磁场变化的主要来源。从上一个太阳活动周期的观测中可以清楚地看出，磁暴期间的环电流动态与地球空间的其他区域强烈耦合。这个项目将结合联合收割机模型和观测，以揭示环电流和这些其他区域之间的联系和反馈。作为拟议工作的一部分，将对两个影响因素进行调查：（1）磁层内离子沉淀区及其与拉伸磁位形的关系，（2）全球磁层振荡及其对环电流的影响。在本研究项目中，选择了一组磁暴进行详细的对比分析。对于每一个重点专题，预计将实现：（1）澄清选定的耦合和反馈机制的性质;（2）增进我们对地球空间作为一个复杂自然系统的认识;（3）提高我们在全球范围模拟磁层系统的能力。分析将采用密歇根大学开发的两个代码。第一个是环电流大气相互作用模型（RAM），它现在包括一个自洽的电场模型。第二个是综合空间环境模型，该模型现在包括磁流体动力学模拟代码和动力学赖斯对流模型之间的双向耦合，从而提高了内磁层结果的准确性。用于约束、验证和/或驱动模拟的数据集包括：地球同步洛斯阿拉莫斯国家实验室（LANL）卫星上的粒子观测;国家海洋和大气管理局/极地运行环境卫星上的离子降水;（NOAA/POES）;来自国防气象卫星计划（DMSP）卫星的热等离子体观测和极帽潜力;高能中性原子（ENA）图像来自磁层顶至极光全球探测成像仪/高能中性原子（IMAGE/HENA）和中能中性原子（MENA）仪器; IMAGE/EUV的等离子体光谱观测（极紫外成像仪）;地球静止运行环境卫星的磁场观测;以及地面磁力计数据。这项研究将成为研究生攻读博士学位的基础。论文研究结果将提高对一些尚未回答的磁暴问题的科学理解，研究结果将通过演讲和出版物公布于众。该项目将增进对全球定位系统误差和卫星异常等造成空间气象影响的一些重要物理过程的科学认识，从而使社会受益。