The Unusual Features in Superstorms

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该项目将结合数据分析和建模来研究：(1)只在最极端的地球空间扰动期间出现或显著改变的现象；(2)它们之间的联系；(3)它们在某些事件中出现而在其他事件中不出现的原因；(4)相关太阳风条件的范围。这些不寻常的特征包括大红色极光，可见的稳定的极光红弧，强低纬度离子-原子极光，极光降水和环电流能谱的软化，强提示穿透电场的外观和效果，以及新发现的在高海拔的亚极光场线上反射的温暖（30 keV）能带离子的强通量。超级磁暴与更典型的磁暴之间的一个关键区别将是研究由警告离子引起的内磁层与下电离层之间耦合的变化。另一个关键的区别是，在对流电喷流中出现了短暂的、高度局部的增强，这似乎是引发大红色极光的部分原因。这项研究将涵盖最近的12次超级风暴，以及各种早期的事件，并与一组更典型的磁暴进行比较，这些磁暴在此期间没有这些现象。此外，比较研究将被用作调查为什么超级风暴在其特征方面不同的工具；为什么一些较小的风暴也包含超级风暴现象；以及由于太阳风驱动因素的不同，超级风暴会发生什么变化。这些研究将使用来自ACE、WIND、FAST、TIMED、IMAGE、Polar、DMSP、NOAA/POES、UARS和LANL地球同步卫星的数据集，以及地面磁力计、光度观测、1996-2005年发生的90次磁暴的HEIDI环电流模拟档案，以及1991-2002年由ami衍生的地磁指数和电动力模式档案。这些数据集都可以在互联网上或密歇根大学本地的开放档案中获得。就更广泛的影响而言，该项目将有助于解决全球太阳-地球耦合问题的国际努力，这需要国际数据集和跨学科合作才能取得进展。这项工作是作为国际日地系统气候和天气（CAWSES）计划的一部分开始的。与巴西国家空间研究所（INPE）的Walter Gonzalez在超级风暴研究课题上的合作是这项早期工作的一个重要成果。这些研究的结果不仅将通过标准期刊传播，而且还将在连接世界科学界的虚拟会议上传播，这些会议计划作为CAWSESII的一个组成部分，为美国研究生和研究人员提供跨学科和国际合作的教育经验，并为发展新的虚拟科学交流形式作出贡献。该项目可以通过提高对极端空间天气下太阳-地球系统复杂性的科学理解，扩大有用预测的范围，从而造福社会。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This project will combine data analysis and modeling to investigate: (1) phenomena that appear, or are significantly modified, only during the most extreme geospace disturbances, (2) the linkages between them, (3) the reasons they appear in some events and not others, and (4) the range of associated solar wind conditions. These unusual features include great red aurorae, visible stable auroral red (SAR) arcs, strong low-latitude ion-atom auroras, softening of both the auroral precipitation and the ring current energy spectrum, appearance and effects of strong prompt penetration electric fields, and newly-discovered intense fluxes of warm ( 30 keV) energy banded ions mirroring at high altitudes on subauroral field lines. The changes in coupling between the inner magnetosphere and underlying ionosphere due to the warn ions will be investigated as one key difference between superstorms and more typical magnetic storms. Another key difference is the occurrence of short-lived, highly localized enhancements in the convection electrojets that seem to play a part in triggering great red auroras. This investigation will cover the twelve most recent superstorms, as well as a variety of earlier events, and compare to a set of more typical magnetic storms during which these phenomena are absent. In addition, comparative studies will be used as tools to investigate why superstorms differ in aspects of their features; why some smaller storms also contain superstorm phenomena; and what changes occur in superstorms as a result of differences in their solar wind drivers. These studies will use data sets from the ACE, WIND, FAST, TIMED, IMAGE, Polar, DMSP, NOAA/POES, UARS, and LANL geosynchronous satellites along with ground-based magnetometers, photometric observations, an archive of HEIDI ring current simulations for 90 magnetic storms that occurred from 1996-2005, and an archive of AMIE-derived geomagnetic indices and electrodynamic patterns from 1991-2002. The data sets are all available in open archives on the Internet or locally at the University of Michigan. In terms of broader impacts, the project will contribute to an international effort to address global sun-to-Earth coupling issues that require international data sets and interdisciplinary collaboration for progress. This effort was started as a component of the international CAWSES (Climate and Weather of the Sun-Earth System) program. The collaboration with Walter Gonzalez at the National Institute for Space Research (INPE) in Brazil on superstorm research topics is an important outcome of this earlier work. Results of the studies will be disseminated not only through standard journals but also in virtual conferences linking the scientific community worldwide that are planned as a component of CAWSESII, contributing to an educational experience in interdisciplinary and international collaborations for US graduate students and researchers and to the development of new forms of virtual scientific communication. The project may benefit society by improving scientific understanding of the complexity in the sun-Earth system during extremes in space weather to extend the range of useful prediction.