A Statistical UltraLow Frequency (ULF) Fingerprint of Magnetic Storms and Its Application to Electron Energization

磁暴统计超低频（ULF）指纹及其在电子赋能中的应用

• 批准号: 0638845
• 负责人: Jeff Sanny
• 金额: $ 13.19万
• 依托单位: Loyola Marymount University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0638845&HistoricalAwards=false
• 关键词: Statistical; UltraLow; Frequency; ULF; Fingerprint

A number of previous investigations have established a close relationship between the solar wind and Ultra-Low Frequency (ULF) waves in the magnetosphere. An area of much recent interest is the rapid enhancement in the number of relativistic electrons in the inner magnetosphere during magnetic storms. While research results have suggested a strong correlation between ULF wave power and high fluxes of these energetic electrons, new fundamental and important questions have been raised. These questions include: (i) how does one differentiate between magnetic storms with relativistic electrons and magnetic storms without relativistic electrons? (ii) what is the relative importance of broadband versus narrowband waves in the energization of relativistic electrons? and (iii) what are the duration and timing of ULF power necessary to produce relativistic electrons? The primary objective of this project is the development of a statistical "fingerprint" of magnetic storms based on a time profile of ULF wave power. Components of this fingerprint will include profiles of the development of Pc3 - 5 powers as well as power indices. This will be done for both intense and moderate magnetic storms as defined using the Dst index. By comparing this fingerprint to the temporal variation of relativistic electron flux, this project will be able to address questions on electron energization such as the ones listed above. The study will be based on over 4 years of geosynchronous satellite observations. During this period, geosynchronous measurements of high-energy electron flux are readily available, and a preliminary survey has revealed the presence of nearly 20 major storms (Dst ~100 nT) and a far greater number of moderate storms, thus allowing for the compilation of a large database well-suited for a statistical study. This project will also include: (1) the integration of research and education, the participation of underrepresented groups, and enhanced research and education infrastructure. Specifically, undergraduates at Loyola Marymount University will be provided the opportunity to participate actively in research, thus enriching their educational experience and providing them with greater preparation for their professional careers. The diversity of the student population at Loyola Marymount will be reflected in the research team. This research will be performed with collaborators at large research institutions, resulting in a partnership that will reinforce the excitement of space physics research among the student scientists.

以前的一些研究已经确定了太阳风和磁层中的超低频波之间的密切关系。最近感兴趣的一个领域是磁暴期间内磁层中相对论电子的数量迅速增加。虽然研究结果表明，超低频波功率与这些高能电子的高通量之间存在很强的相关性，但也提出了新的基本和重要的问题。这些问题包括：(I)如何区分有相对论电子的磁暴和没有相对论电子的磁暴？(Ii)在相对论电子的能化过程中，宽带波与窄带波的相对重要性是什么？以及(Iii)产生相对论电子所需的超低频功率的持续时间和时间是多少？该项目的主要目标是根据超低频波功率的时间分布，开发磁暴的统计“指纹”。该指纹的组成部分将包括PC3-5电源的发展概况以及电源指数。这将适用于使用DST指数定义的强磁暴和中等磁暴。通过将这个指纹与相对论电子通量的时间变化进行比较，这个项目将能够解决上面列出的关于电子能量的问题。这项研究将基于4年多的地球同步卫星观测。在此期间，高能电子通量的地球同步测量是现成的，初步调查显示存在近20个主要风暴(DST~100 nT)和更多的中等风暴，从而可以汇编一个适合统计研究的大型数据库。该项目还将包括：(1)研究与教育的结合、代表性不足的群体的参与以及加强研究和教育基础设施。具体来说，Loyola Marymount大学的本科生将有机会积极参与研究，从而丰富他们的教育经验，为他们的职业生涯做好更好的准备。洛约拉·马里蒙特的学生群体的多样性将在研究团队中得到反映。这项研究将与大型研究机构的合作者一起进行，从而形成一种伙伴关系，这将加强学生科学家对空间物理研究的兴奋。