Collaborative Research: Dayside Field-Aligned Current (FAC) Source Regions of Extreme Poynting Flux Events and the Response of the Magnetosphere-Ionosphere-Thermosphere System

合作研究：极端坡印廷通量事件的日侧场对准电流（FAC）源区以及磁层-电离层-热层系统的响应

• 批准号: 1144062
• 负责人: Geoffrey Crowley
• 金额: $ 22.79万
• 依托单位: ATMOSPHERIC & SPACE TECHNOLOGY RESEARCH ASSOCIATES, L.L.C.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1144062&HistoricalAwards=false
• 关键词: Collaborative; Research; Dayside; Field; Aligned

Most studies of the magnetosphere have been carried out by considering primarily the north-south (Bz) component of the interplanetary magnetic field (IMF) and most of those have considered intervals with southward IMF (Bz0). Recent discoveries have revealed anomalous thermospheric neutral density signatures caused by intense deposition of Poynting flux delivered over very localized regions under conditions that are normally considered benign. These studies have shown that relatively modest IMF By-driven localized heating at storm-onset generates neutral thermospheric disturbances that had not previously been explained. In addition studies using data from DMSP satellites demonstrated large yet localized dayside energy input. MHD simulation results for one case suggest that the localized enhanced Poynting fluxes in the southern hemisphere map to a flank magnetopause reconnection region. Most of these events are associated with dominant in-the-ecliptic interplanetary magnetic field (IMF) values, often, but not exclusively, while the IMF Bz is northward (Bz0). The objectives of this proposal are to verify the source region (magnetopause merging versus bow shock) of the Poynting flux-related dayside field-aligned currents (FACs), determine their ionospheric distribution, and examine the relative local and global impact of the Poynting flux energy input on the magnetosphere-ionosphere-thermosphere system. The influences of solar ejecta and high-speed streams will be distinguished and investigated for seasonal and hemispheric differences. The study will employ both data analysis from multiple satellites, ground based observations from radar and the AMIE technique and tie all the observations together with global magnetohydrodynamic simulations. This research potentially transforms the way the space science community views the effects of non-southward IMF on the geospace environment. It is at the forefront of system science in exploring the influence of non-southward IMF on the field-aligned currents that deliver focused energy to dayside regions. This is an understudied area of space physics. It also has practical application to problems related to satellite drag.

对磁层的大多数研究主要考虑行星际磁场的南北分量，其中大多数研究考虑了行星际磁场向南的间隔（Bz 0）。最近的发现揭示了异常的热层中性密度特征，这是由于在通常被认为是良性的条件下，在非常局部的区域上输送的坡印廷通量的强烈沉积造成的。这些研究表明，相对温和的国际货币基金组织在风暴开始驱动的局部加热产生中性热层扰动，以前没有得到解释。此外，利用DMSP卫星数据进行的研究表明，昼侧能量输入量很大，但很局限。一个例子的MHD模拟结果表明，在南半球的局部增强坡印亭通量映射到一个侧翼磁层顶重联区。大多数这些事件与占主导地位的黄道行星际磁场（IMF）值有关，通常但不完全是，而IMF Bz是向北的（Bz 0）。本提案的目标是验证坡印廷通量相关的向阳面场向电流（FACs）的源区（磁层顶合并与弓形激波），确定其电离层分布，并检查坡印廷通量能量输入对磁层-电离层-热层系统的相对局部和全球影响。将区分太阳喷出物和高速气流的影响，并研究季节和半球差异。该研究将采用多颗卫星的数据分析、雷达的地面观测和AMIE技术，并将所有观测与全球磁流体动力学模拟联系在一起。这项研究有可能改变空间科学界对非南向IMF对地球空间环境影响的看法。 它处于系统科学的前沿，探索非南向IMF对向昼侧区域提供集中能量的场向电流的影响。这是空间物理学的一个未充分研究的领域。它也可实际应用于与卫星阻力有关的问题。