Conjugate Studies of ULF Waves and Magnetospheric Dynamics Using Ground-Based Induction Magnetometers at Four High-Latitude Manned Sites

在四个高纬度载人站点使用地基感应磁力计进行 ULF 波和磁层动力学的共轭研究

• 批准号: 0233169
• 负责人: Mark Engebretson
• 金额: $ 42.62万
• 依托单位: Augsburg University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0233169&HistoricalAwards=false
• 关键词: Conjugate; Studies; ULF; Waves; Magnetospheric

Since the beginning of the space age increasingly sophisticated efforts have been made to explore and understand Earth's space environment. Scientists now understand much about the configuration of the ionosphere and the region above it, the magnetosphere, but much remains to be done before we fully understand the dynamical processes involved in transferring energy and momentum from the rapidly changing solar wind (driven by both quiescent and explosive processes near the surface of the Sun) into Earth's magnetosphere, ionosphere, and upper atmosphere. It is increasingly understood that doing so requires the coordinated use of multiple data sets, including both a variety of individual spacecraft and strategically located ground observatories. Because those parts of Earth's field that reach farthest out into space intersect the ground at high latitudes, arrays of ground magnetometers have long been a valued means of monitoring processes in remote parts of the magnetosphere. This proposal requests support to continue to operate and analyze data from four search coil magnetometers located at high latitude sites in the North American sector, two in Antarctica (South Pole and McMurdo) and two in the Arctic (Sondrestromfjord, Greenland, and Iqaluit, Nunavut, Canada). South Pole and Iqaluit provide close magnetic conjugacy near-cusp latitudes, while Iqaluit and Sondrestromfjord provide data at similar northern latitudes but with a local time separation of 1.5 hours. During daytime hours these locations provide a window to the magnetospheric boundary and the interactions of the magnetosheath with the magnetosphere, and during nighttime hours they provide an increasingly appreciated high-latitude perspective on the development of substorm activity. The proposers are also involved in analysis of data from other high latitude arrays of ground-based instruments, including the multi-instrument U.S. and British AGO (Automated Geophysical Observatory) and developing autonomous magnetometer arrays in Antarctica, and the MACCS and CANOPUS magnetometer arrays in Arctic Canada. The 10 Hz sampling rate of the search coil magnetometers in this project provide an important complement to the more limited sampling rates of other search coil and fluxgate magnetometer systems (= 2 Hz) in these regions. Taken together, these instruments make it possible to study the entire range of ULF variations, from Pc 1 and Pi 1 pulsations down to Pc 5 pulsations, with high sensitivity. In conjunction with data from other instruments located at the Antarctic sites and with both low-altitude and high-altitude satellites, these magnetometers have played, and we expect will continue to play, a significant role in a variety of studies of geospace phenomena. During the next three years we expect our scientific efforts to focus on (a) studies of several classes of Pc 1 and 2 waves (0.2-1 Hz), including waves observed poleward of the cusp, so-called "mantle waves"; (b) the propagation of Pc 3-4 pulsations and the generation of quasiperiodic (QP) emissions, a class of ELF/VLF emissions modulated at Pc 3-4 frequencies (15-60 mHz); and (c) studies of both short-period and long-period irregular ULF waves, especially during substorms and magnetic storm periods. Analysis and data processing efforts associated with these data sets are highly suitable for undergraduate as well as graduate research participation, and build on continuing strong programs of faculty and undergraduate student research.

自空间时代开始以来，为探索和了解地球的空间环境作出了越来越复杂的努力。科学家们现在对电离层及其上方的区域--磁层的结构有了很多了解，但在我们完全了解从快速变化的太阳风(由太阳表面附近的静止和爆炸过程驱动)向地球磁层、电离层和高层大气传递能量和动量所涉及的动力学过程之前，还有很多工作要做。人们越来越认识到，这样做需要协调使用多个数据集，包括各种单独的航天器和位于战略位置的地面观测站。由于地球磁场中延伸到太空最远的部分在高纬度与地面相交，地面磁力计阵列长期以来一直是监测磁层偏远部分过程的重要手段。该提案要求提供支助，以继续运行和分析位于北美地区高纬度地区的四个搜索线圈磁力仪的数据，其中两个位于南极洲(南极和麦克默多)，两个位于北极(格陵兰的Sondrestromfjord和加拿大努纳武特的Iqaluit)。南极和Iqaluit提供接近尖点纬度的紧密磁共轭，而Iqaluit和Sondrestromfjord提供类似北纬的数据，但当地时间相差1.5小时。在白天，这些地点为了解磁层边界和磁鞘与磁层的相互作用提供了一个窗口，而在夜间，它们提供了一个越来越受重视的关于亚暴活动发展的高纬度视角。提出者还参与了对其他高纬度地面仪器阵列的数据分析，其中包括美国和英国的多仪器AGO(自动地球物理观测站)和正在开发的南极洲自主磁强计阵列，以及加拿大北极的MACCS和Canopus磁强计阵列。本项目中搜索线圈磁力仪的10赫兹采样率是对这些地区其他搜索线圈和磁通门磁力仪系统(=2赫兹)采样率较为有限的重要补充。这些仪器结合在一起，使得以高灵敏度研究从Pc1和Pi 1脉动到Pc5脉动的整个ULF变化范围成为可能。这些磁力计与设在南极地点的其他仪器以及低空和高空卫星的数据一起，在地球空间现象的各种研究中发挥了重要作用，我们预计将继续发挥重要作用。在今后三年内，我们预计我们的科学努力将集中于：(A)研究几类Pc1和2波(0.2-1赫兹)，包括观察到的尖端极向波，即所谓的“地幔波”；(B)Pc3-4脉动的传播和准周期辐射的产生，这是一类在Pc3-4频率(15-60兆赫)调制的甚低频/甚低频辐射；(C)研究短周期和长周期的不规则极低频波，特别是在亚暴和磁暴期间。与这些数据集相关的分析和数据处理工作非常适合本科生和研究生的研究参与，并建立在教师和本科生研究的持续强大计划的基础上。