CAREER: Observational and Modeling Investigations of Pulsating Aurora Electrodynamics

极光是一种高纬度现象，以弧线、床单、窗帘等形式可见。一种常见的极光被称为脉动极光，它包括开关调制。这种壮观的特征是由自然发生的辐射造成的，它们的强度取决于高纬度地区的沉淀电子，而这反过来又会影响能量的沉积。沉积的能量可以以重力波的形式传播出去，并且可以影响其他纬度区域。高能粒子降水与不同的极光有关，特别是脉动极光，可以引起电离层上层区域的增强，电离层吸收高频无线电波传播。这将影响通信系统，这些系统对于需要向地面开放连续通信链路的跨极飞行至关重要。本次研究的重点是了解脉动极光，这是观测最多的极光类型之一。脉动极光虽然普遍存在，但其电动力学还没有像其他类型的极光那样得到详细的研究。本研究旨在解决与时间变化系统的电动力学相关的基本问题，该系统由脉动极光事件期间发生的开关调制驱动。教育方面的努力包括为未被充分代表的少数民族（URM）中学生提供空间科学暑期研究经验，并为克莱姆森大学的本科生建立NASA Rocksat-X计划。这些活动将促进学术（克莱姆森大学）、非学术、非营利组织（皮斯加天文研究所）和社区伙伴（利特尔约翰社区中心）之间的合作。极光事件中电子沉降的增强改变了电离层的电导率，因此对脉动极光的研究为扩展高纬度地区的电动力学知识提供了一个极好的机会。作为这项工作的一部分，将解决两个科学问题：(a)脉动极光的电场、电流和电导率结构是什么？(b)脉动极光降水的平均能量和能量通量的时间变化如何影响电导率？为了实现第一个目标，该方法将利用Poker Flat非相干散射雷达数据，并使用离子中性相互作用（GEMINI）电离层模型的三维地球空间环境模型对脉动极光电动力学进行建模研究。双子座的建模模拟将在理想的脉动极光和实际事件中进行，其中全天成像仪和PFISR数据将用于驱动模型。为实现第二个目标，建议利用Poker Flat DPS-4D Digisonde、全天成像仪观测，并在Poker Flat研究靶场部署高频（HF）无线电接收机和发射机。此外，将开发一项新技术，利用高时间分辨率的高频无线电波观测来捕捉脉动极光期间发生的快速电离层和相关的电动力学变化。该项目由GEO理事会AGS分部的航空计划和美国国家科学基金会刺激竞争性研究的既定计划（EPSCoR）共同资助。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。

Aurora is a high latitude phenomenon and is visible as arcs, sheets, curtains, etc. One common variety is referred to as pulsating aurora that includes on-and-off modulations. This spectacular feature results from the natural occurring emissions, and their intensity depends on precipitating electrons at high latitudes, which in turn can influence energy deposition. Deposited energy can be propagated away in the form of gravity waves and can affect other latitudinal regions. Energetic particle precipitation associated with different aurora, and in particular pulsating aurora, can cause enhancements in the upper regions of the ionosphere, which absorbs high-frequency radio wave propagation. This impacts communication systems that are important for transpolar flights requiring continuous communication links to be open to the ground. The focus of this investigation is specifically to understand pulsating aurora, which is one of the most observed auroral types. Despite its ubiquitous occurrence, the electrodynamics of pulsating aurora have not been investigated in detail as other kinds of aurora. This investigation intends to address fundamental problems associated with the electrodynamics of a time changing system, driven by the on-and-off modulations occurring during pulsating auroral events. Educational efforts include a space science summer research experience for underrepresented minority (URM) middle school students and establishment of a NASA Rocksat-X program for undergraduate students at Clemson University. The activities will promote collaboration between academic (Clemson University) and non-academic, non-profit organization (Pisgah Astronomical Research Institute) and community partner (Littlejohn Community Center). Enhanced electron precipitation during auroral events modifies ionospheric conductivity, and thus investigation of pulsating aurora offers an excellent opportunity to expand knowledge about electrodynamics of the high latitude regions. Two scientific questions that will be addressed as a part of this effort are (a) What is the electric field, current, and conductivity structure of pulsating aurora? and (b) How do temporal changes in the average energy and energy flux of the pulsating aurora precipitation affect the conductivity? To address the first objective, the methodology will utilize Poker Flat incoherent scatter radar data and perform modeling investigations of pulsating aurora electrodynamics using the 3-D Geospace Environment Model of Ion-Neutral Interactions (GEMINI) ionosphere model. The GEMINI modeling simulations will be conducted on idealized pulsating aurora and actual events in which all-sky imager and PFISR data will be used to drive the model. To achieve the second goal, utilization of the Poker Flat DPS-4D Digisonde, all-sky imager observations, and deployment of high frequency (HF) radio receivers and transmitters at Poker Flat Research Range are suggested. Additionally, a new technique will be developed that will leverage HF radio wave observations at high temporal resolution to capture fast ionospheric and associated electrodynamical changes occurring during the pulsating aurora. This project is jointly funded by Aeronomy program, in the AGS Division of the GEO directorate and the Established Program to Stimulate Competitive Research (EPSCoR) at the NSF.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.