GEM: Sources of Electron Populations in the Plasma Sheet

地球的磁尾区域充满了来自太阳风和地球电离层的带电粒子，形成了等离子体片。 这项研究的重点是回答为什么等离子体片电子被观察到的方式，他们从哪里来。 该小组将开发一个基于数据的模型（包括经验关系）的多个电子人口特征在近地等离子体片。 一名女性首席调查员将领导这一项目，扩大代表性不足群体的参与。 博士后的大量参与将促进早期职业劳动力的培训和学习机会。 该项目的成果将被纳入密歇根大学的现有课程，并通过课堂演示、科学会议和出版物传播。 这项工作的主要目标是定义在近地等离子体片（6-12 RE）的多个电子种群的来源和它们的作用，在形成特定形状的电子分布函数使用相互校准的THEMIS ESA和SST数据从整个操作期间。 具有不同温度的多个电子群体可以指示不同的源，例如，地幔粒子通过远尾进入，磁鞘粒子通过侧面磁层顶进入，电离层流出。 不同的群体可以具有不同的各向异性。 当电子布居的来源是已知的，它们的建模变得更容易实现。 作为研究的一个成果，通过太阳风、IMF参数、地磁活动指数和电离层参数（例如，极盖电位）将被开发。 获得近地等离子体片中电子总数的详细图像是重要的，具有高度的科学优先性。 对THEMIS航天器在近地等离子体片中地球静止距离以外提供的电子数据进行的详细分析是一项独特的调查，同时也是对正在进行的其他数据研究的补充，例如，货车艾伦探测器数据。该奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响力的支持审查标准。

Earth's magnetotail region is filled with charged particles from the solar wind and the terrestrial ionosphere, forming the plasma sheet. The research focuses on answering why the plasma sheet electrons are observed in the way they are and where they come from. The team will develop a data-based model (including empirical relations) of multiple electron population characteristics in the near-Earth plasma sheet. A female principal investigator will lead this project, expanding participation among underrepresented groups. The heavy involvement of a postdoc will promote training and learning opportunities for the early-career workforce. Results from this project are intended to be incorporated into existing courses at the University of Michigan and disseminated via presentations in the classroom, scientific meetings, and publication. The primary objective of this effort is to define the sources of multiple electron populations in the near-Earth plasma sheet (6-12 RE) and their roles in forming specific shapes of electron distribution functions using inter-calibrated THEMIS ESA and SST data from the whole period of operation. Multiple electron populations with different temperatures may indicate the different sources, e.g., the mantle particles entering through the distant tail and the magnetosheath particles entering through the flank magnetopause, ionosphere outflow. Different populations can have different anisotropy. When the sources of electron populations are known, the modeling of them becomes more achievable. As a product of the investigation, a data-based model (including empirical relations) of multiple electron population characteristics in the near-Earth plasma sheet (moments and fluxes) parameterized by the solar wind, IMF parameters, geomagnetic activity indices, and ionosphere parameters (e.g., polar cap potential) will be developed. Obtaining a detailed picture of the electron population in the near-Earth plasma sheet is important and of high scientific priority. The detailed analysis of the electron data provided by THEMIS spacecraft outside the geostationary distances in the near-Earth plasma sheet is a unique investigation and, at the same time, complementary to the ongoing studies with other data, such as, for example, Van Allen Probes data.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.