Testing the Validity of Inner-magnetosphere Shielding by the Region-2 Field-aligned Currents

地球大气层的外层与太阳风相互作用。科学家们仍然不知道能量是如何从太阳风中传输到每一层低密度等离子体的过程。这项工作研究了这些能量传输过程是如何从磁层发生到电离层的。该项目与国家空间天气行动计划有关，因为它将协助确定观测到的极端空间天气影响所产生的电离层扰动的典型限度。这些干扰影响卫星轨道，可能危及我们美国商业和国防资产的跟踪和运作。将支持一名早期职业科学家和本科生研究人员。由于电荷分离而产生的屏蔽电场与2区场对准电流（FAC）有关，在决定耦合内磁层-电离层系统的动力学中起着重要作用。然而，亚极光区域的场向电流和电场的全球尺度测量的缺乏限制了我们对内磁层屏蔽动力学的理解，并且有几个问题仍未得到解答。具体来说，(1)屏蔽范式在多大程度上是有效的？(2)与屏蔽相关的时间尺度是什么？(3)季节和当地时间如何影响屏蔽？这项工作的总体目标是通过使用美国国家科学基金会资助的主动磁层和行星电动力学响应实验（AMPERE）数据集的测量结果来回答这些问题，以确定1区和2区FACs之间的不平衡，作为屏蔽强度的代理。具体任务将集中在将AMPERE fas与中纬度超级双极光雷达网络（SuperDARN）的电场结合起来，以确定2区fas对内磁层屏蔽范式的有效程度，并确定电离层电导率和MLT对屏蔽过/屏蔽不足电场的大小、范围和时间尺度的调制影响。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 outer layers of the Earth's atmosphere interact with the solar wind. Scientists still do not understand the process of how energy is transported from the solar wind throughout each of these layers of low-density, plasmas. This work investigates how these energy transport processes occur from the magnetosphere into the ionosphere. The project is relevant to the National Space Weather Action Plan since it will assist in identifying typical limits of ionospheric disturbances generated from extremes of observed space weather effects. These disturbances affect the orbits of satellites that can compromise tracking and operations of our US commercial and defense assets. An early career scientist and undergraduate researchers will be supported.The shielding electric field generated due to charge separation associated with the Region-2 Field Aligned Currents (FAC) plays an important role in determining the dynamics of the coupled inner magnetosphere-ionosphere system. However, the paucity of global-scale measurements of field-aligned currents and electric fields in the sub-auroral region has restricted our understanding of the dynamics of inner magnetosphere shielding and several questions remain unanswered. Specifically, (1) To what extent is the paradigm of shielding valid?, (2) What are the timescales associated with shielding?, and (3) How do season and local time influence shielding? The overarching goal of this work is to answer these questions by using measurements from the NSF-funded Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) dataset to determine the imbalance between the Region-1 and Region-2 FACs as a proxy for the intensity of shielding. Specific tasks will focus on combining AMPERE FACs with electric fields from the mid-latitude Super Dual Auroral Radar Network (SuperDARN) to determine the extent to which the paradigm of inner magnetosphere shielding by Region-2 FACs is valid and to determine the modulating influence of ionospheric conductivity and MLT on the magnitude, extent and timescales of over-/under-shielding electric fields.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.