Comprehensive Study of 3D Magnetosphere-Ionospheric Current System Through the Modeling, Observations, and Applications: Auroral Electrojet Indices for the Southern Hemisphere

地球三维磁层-电离层电流系统是地球空间环境的重要组成部分。这些电流是由太阳风（来自太阳的永久等离子体流）与地球磁层的相互作用驱动的，通过与地磁场对齐的电流将大量的能量和动量转移到高纬度电离层和高层大气中。三维电流系统动态影响着北极和南极地区，通过地球电离层中这些电流的关闭导致它们的动态变化和加热。这些电流可以建模，但很难从地面甚至从太空观察到它们——只有它们对地磁场变化的影响（以及地磁活动的相应指数）才能通过适当放置的地面仪器记录下来。该奖项将通过开发模型并将模型结果与地面和卫星观测结果进行比较，支持对半球间场向流这一相对未被探索的现象进行研究。这个新模型将极大地促进我们对两个半球空间天气驱动过程的物理学的理解，并开发一个描述南极地区地磁活动的指数。后者很重要，因为使用现有的声波电喷（AE）技术（使用横跨北极光区的12个地磁观测站的数据）计算该指数不适用于覆盖全球约50%的南大洋的南极光区。目前仅有5-6个南极沿海科考站可以参与该指数的计算，这对于传统的声发射计算技术来说远远不够理想。这项研究工作有可能大大增加我们对半球间电流在极地和极光区动力学中所起作用的理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Earth's three-dimensional magnetosphere-ionosphere current system is an important component of the Geospace environment. These currents are driven by the interaction of solar wind (an everlasting plasma flow from the Sun) with the Earth's magnetosphere, transferring significant amounts of energy and momentum into the high-latitude ionosphere and upper atmosphere via the geomagnetic field-aligned currents. The 3D current system dynamics affect both the Northern and South Polar Regions, causing their dynamic changes and heating through the closure of these currents in the Earth's ionosphere. These currents can be modeled, but they are difficult to observe from the ground or even from space - only their effects on geomagnetic field variations (and respective indices of geomagnetic activity) can be recorded by properly placed ground-based instruments. This award will support a study of a relatively unexplored phenomenon of interhemispheric field-aligned currents through the model development and comparison of modeled results with the ground-based and satellites observations. This new model will significantly advance our understanding of the physics of space weather-driving processes in both hemispheres and development of an index describing geomagnetic activities in the Southern polar region. The latter is important because calculating this index using existing Aural Electrojet (AE) technique (that uses data from 12 geomagnetic observatories across the Northern auroral region) is not applicable to the Southern auroral region that goes over Southern Ocean for ~50% of the global coverage. There are only 5-6 Antarctic costal research stations that can contribute to this index calculations, which is much less than optimal for the traditional AE calculation technique. This research effort has the potential to significantly increase our understanding of the role played by interhemispheric currents on the dynamics of the polar and auroral regions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.