Kelvin-Helmholtz Instability and Magnetosonic Wave Emission Along Bursty Bulk Flow Channel Boudaries: Impacts on Near-Earth Plasma Sheet Dynamics During Substorms

亚暴是空间气象应用的关键要素，也是太阳风在地球磁层储存和释放能量的基本过程。了解亚暴动力学对于为极端空间天气事件做准备至关重要，极端空间天气事件会对星载和地面技术系统的性能和可靠性造成强烈的破坏和破坏。在影响亚暴动力学的众多物理现象中，磁尾的不稳定性近年来受到了广泛的关注。本项目将研究开尔文-亥姆霍兹不稳定性（KHI）和磁流体动力学（MHD）波沿爆发体流（bbf）的演变及其对亚暴动力学的潜在影响。该项目的结果将扩大我们对磁尾的MHD波和不稳定性及其与亚风暴动力学的关系的理解，这将有助于更好地理解磁层-电离层耦合。因此，该项目的成果将直接应用于积极发展空间天气准备和建设预测空间天气影响的能力，支持国家空间天气行动计划的最新重点。该项目还将支持来自一个未被充分代表的群体的早期职业女性科学家，以支持NSF在多样性和促进女性在科学领域的进步方面的战略目标。此外，该项目将通过让来自尤蒂卡大学（主要是本科院校）的本科生和来自大尤蒂卡地区少数民族的高中生作为暑期研究学生，为NSF发展多元化和具有全球竞争力的STEM劳动力的目标做出贡献。激发这项研究的首要问题是：MHD波是否沿着bbf发生，如果是这样，这些MHD波是如何影响亚暴动力学的？沿bbf的KHI和MHD波发射与相关的亚暴动力学之间的关系是什么？具体来说：(1)与bbf相关的MHD波的可能存在是什么？如果它们存在，那么哪种太阳风条件更有利于这些MHD波的发射？(2)如果存在MHD波，它们是否经常伴随着KHI沿bbf的演变？如果在MHD波发射期间没有KHI演化，那么还有什么其他机制可能引起这些波？随着KHI的演化，MHD波发射的频率和条件是什么？(3)这些MHD波的特征是什么，频率、周期、相速度等？它们是否与在bbf附近观测到的超低频波特征一致？(4)这些MHD波如何影响bbf的动力学？(5)这些MHD波在电离层中的特征是什么？该团队将使用NASA社区协调建模中心（CCMC）提供的CMIT-LFM耦合全球MHD模拟代码。模拟结果将与来自亚风暴期间事件和宏观尺度相互作用的时间历史（THEMIS）和来自加拿大磁活动实时调查阵列（CARISMA）的地面观测结果进行验证。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。

Substorms are key elements of space weather applications and fundamental processes of solar wind energy storage and release in Earth's magnetosphere. Understanding substorm dynamics is essential in preparing for extreme space weather events, which can cause strong disruption and damage to the performances and the reliability of space-borne and ground-based technological systems. Among many physical phenomena affecting the substorm dynamics, instabilities in the magnetotail have caught much attention in recent years. This project will investigate the evolution of Kelvin-Helmholtz Instability (KHI) and magnetohydrodynamics (MHD) wave emission along Bursty Bulk Flows (BBFs) and their potential impacts on the substorm dynamics. The project results will expand our understanding of MHD waves and instabilities in the magnetotail and their association with the substorm dynamics, which will contribute to a better understanding of the magnetosphere-ionosphere coupling. Therefore, the results of this project will have direct applications in the active development of Space Weather preparedness and building capabilities to forecast space weather effects, supporting the latest focus of the National Space Weather Action Plan. This project will also support an early career female scientist from an underrepresented group, which supports NSF's Strategic Goals in diversity and promoting the advancement of women in science. Furthermore, this project will contribute to NSF's goal of developing a diverse and globally competitive STEM workforce" by involving undergraduate students from Utica University (a primarily undergraduate institution) and high school students from minority groups in the greater Utica area as summer research students. The overarching questions that motivate this investigation are: Do MHD waves occur along BBFs, and if so, how do these MHD waves impact substorm dynamics? What is the relationship between the KHI and MHD waves emission along BBFs and associated substorm dynamics? Specifically: (1) What is the likely presence of MHD waves associated with BBFs? If they are present, which solar wind conditions are more favorable for the emission of these MHD waves? (2) If MHD waves are present, are they often accompanied by KHI evolution along the BBFs? If KHI evolution is absent during MHD wave emission, what other mechanisms might cause these waves? How often and under what conditions MHD wave emission occurs with KHI evolution? (3) What are the characteristics of these MHD waves, frequencies, periods, phase velocities, etc.? Do they agree with the observed ULF wave characteristics near BBFs? (4) How do these MHD waves affect BBFs' dynamics? (5) What are the signatures of these MHD waves in the ionosphere? The team will use CMIT-LFM coupled global MHD simulations code available at NASA's Community Coordinated Modeling Center (CCMC). Simulation results will be verified with observations from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) and ground-based observations from the Canadian Array for Realtime Investigations of Magnetic Activity (CARISMA).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.