GEM: Resolving the Unique Characteristics of Substorms that Precede Strong Thermal Emission Velocity Enhancement (STEVE) Events

GEM：解决强热发射速度增强 (STEVE) 事件之前的亚暴的独特特征

• 批准号: 2225972
• 负责人: Lindsay Goodwin
• 金额: $ 39.21万
• 依托单位: New Jersey Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2225972&HistoricalAwards=false
• 关键词: GEM; Resolving; Unique; Characteristics; Substorms

A Strong Thermal Emission Velocity Enhancement (STEVE) is a latitudinally narrow and longitudinally elongated optical emission that appears in the night sky before midnight, equatorward of the auroral oval. Importantly, STEVE is not an aurora in the classic sense - as far as we can tell STEVE's emissions are not generated by charged particles streaming down magnetic field lines and colliding with the neutral atmosphere to produce optical emissions. In fact, the exact mechanism for STEVE's optical emissions have yet to be identified. However, STEVEs are correlated with events called substorms which involve energy releases in the Earth's nightside magnetic field, which often manifest as dynamic auroral displays. This research focuses on the observation that most substorms do not result in a STEVE event (approximately only 3% do), indicating that substorms that occur with STEVE events are unique. To better understand STEVE associated substorms and the conditions under which STEVEs occur, we will use data from all-sky imagers, spacecraft, radars, magnetometers, and citizen scientists – who were the ones who initially discovered STEVE. Using these datasets, the evolution from substorm to STEVE (or no STEVE) will be monitored. Additionally, we will investigate and specify the geomagnetic conditions unique to STEVE events. This work will strengthen our understanding of the upper atmosphere and the near-Earth geospace environment, allowing us to better mitigate space weather effects. Furthermore, given the team and collaborations this project will support, this research will promote education and diversity, and strengthen collaborations within the solar-terrestrial science community.Strong Thermal Emission Velocity Enhancement (STEVE) events are bright mauve optical emissions that periodically occur between dusk and midnight in subauroral regions after a substorm onset. It has been established that STEVE is correlated with substorms, and more specifically the recovery phase of a substorm. Importantly, not all substorms are associated with a STEVE event, but all STEVE events are associated with a substorm. The motivation of this work is to determine how the substorms associated with STEVE events are unique compared to other substorms. This will be done by addressing three science questions: 1) What is the temporal response of the magnetosphere-ionosphere system to substorm onset in associated STEVE events? 2) What are the conditions of the magnetosphere-ionosphere system prior to a STEVE event; can preconditioning be identified? and 3) How are the auroral and sub-auroral mesoscale flow patterns associated with STEVE events different from those associated with substorm events in general? We will use all-sky imagers, spacecraft, radars, magnetometers, and citizen science data to address the aforementioned questions. A novel and compelling component of this research effort will be the incorporation of radar data, in particular Incoherent Scatter Radar (ISR) data. This will allow us to complement existing measurements provided by imagers and spacecraft and also enhance our ability to identify undiscovered STEVE events. The ionospheric signature of a STEVE event in ISR data has recently been identified and will be used to find and characterize additional STEVE events in the work.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.

强烈的热发射速度增强（Steve）是一种纬度狭窄且纵向伸长的光学发射，它出现在午夜前的夜空中，在Aurora椭圆形的位置。重要的是，史蒂夫不是经典意义上的极光 - 据我们所知，史蒂夫的排放不是通过流向磁场线条并与中性气氛相撞以产生光学排放的带电颗粒产生的。实际上，史蒂夫光学排放的确切机制尚未确定。然而，史蒂夫与称为实体的事件相关，该事件涉及地球夜间磁场中的能量释放，这通常表现为动态的极光显示器。这项研究的重点是观察到，大多数实体不会导致史蒂夫事件（大约3％的事件），这表明史蒂夫事件发生的实体是唯一的。为了更好地理解史蒂夫相关的替代物和史蒂夫的情况，我们将使用来自最初发现史蒂夫的全天空图像，航天器，雷达，磁力仪和公民科学家的数据。使用这些数据集，将监视从实量到史蒂夫（或没有史蒂夫）的演变。此外，我们将研究并指定史蒂夫事件独有的地磁条件。工作将加强我们对高层大气和近地地图上环境的理解，从而使我们能够更好地减轻空间天气影响。此外，鉴于该项目将支持团队和合作，这项研究将促进教育和多样性，并加强太阳能科学社区内的合作。施加热排放速度增强（Steve）事件是明亮的梅夫光学排放，这些效率是明亮的梅夫光学排放，这些排放量会定期出现在替代区域后的黄昏和午夜之间。已经确定，史蒂夫与化型相关，更具体地说是一个质量的恢复阶段。重要的是，并非所有实量都与史蒂夫事件相关联，但所有史蒂夫事件都与实量相关联。这项工作的动机是确定与史蒂夫事件相关的构成与其他实体相比的独特之处。这将通过解决三个科学问题来完成：1）在相关的史蒂夫事件中，磁层 - 离子层系统的临时响应是什么？ 2）在发生史蒂夫事件之前，磁层 - 离子层系统的条件是什么？可以确定预处理吗？ 3）与史蒂夫事件相关的极光和次级次级中尺度流动模式与一般与替代事件相关的事件有何不同？我们将使用全天空的图像，航天器，雷达，磁力仪和公民科学数据来解决优先问题。这项研究工作的一种新颖而引人注目的组成部分将是雷达数据的结合，特别是不连贯的散点雷达（ISR）数据。这将使我们能够完成图像仪和航天器提供的现有测量结果，并增强我们确定未发现的史蒂夫事件的能力。最近已经确定了ISR数据中史蒂夫事件的电离层签名，并将用于查找和表征工作中其他史蒂夫事件。该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响来评估NSF的法定任务。