NSWP: Sustained Sub-auroral Storm Electric Fields: Polarization or Minimum Dissipation?

这是一个为期三年的研究项目，使用来自沃洛普斯岛的新超级雷达的数据，以及DMSP和铱星的数据来调查和引出所谓的亚极光偏振流（SAPS）的起源。首要的科学问题与磁层-电离层耦合有关，即电离层是否被动地响应磁层中的情况，或者电离层是否应该被认为与磁层更紧密地耦合，从而影响整个磁层-电离层对太阳风驱动器的响应。将解决的具体科学目标包括：1)量化回流中的黎明-黄昏不对称性，包括其随IMF时钟角度的变化；2)量化颗粒降水强度和纬度的不对称性及其与回流强度、Birkeland海流和IMF时钟角的关系；3)确定包括环流物理在内的磁层内对流是否可以解释观测到的流动和Birkeland流分布，或者没有离子漂移物理的MHD物理是否可以解释观测到的回流分布。这一努力的智力价值在于大大提高了我们对风暴时期磁层-电离层系统和活跃时期中纬度电动力学的理解。这种理解对于推进对地磁风暴的基础科学理解是必要的，但也适用于重要的实际领域，如通信和导航，对这些领域来说，电离层强电场是最重要的。该项目还延续了APL与奥格斯堡学院物理系之间的非正式合作关系，包括通过JHU/APL学生暑期实习计划为来自奥格斯堡的APL本科生提供暑期研究机会。磁暴过程中的M-I耦合是影响极地高层大气电动力学的重要物理过程之一。因此，该研究项目将有助于国家科学基金会国际极地年计划的更大研究目标。

This is a three year research project to use data from the new SuperDARN radar at Wallops Island, as well as DMSP and Iridium satellite data to investigate and elicit the origins of what is known as Subauroral Polarization Streams (SAPS). The overarching science question is related to magnetosphere-ionosphere coupling, that is whether the ionosphere passively responds to the situation in the magnetosphere or whether the ionosphere should be considered as more tightly coupled to the magnetosphere so that it influences the whole magnetosphere-ionosphere response to the solar wind drivers. Specific science goals that will be addressed include 1) Quantifying the dawn-dusk asymmetry in the return flow including its variation with IMF clock angle; 2) Quantifying the asymmetry in intensity and latitude of particle precipitation and its relationship to: the return flow intensity, the Birkeland currents, and the IMF clock angle; 3) Determining whether inner magnetospheric convection including ring current physics can account for the observed distributions of flows and Birkeland currents or whether MHD physics without ion drift physics can account for the observed distribution of return flows. The intellectual merit of this effort lies in significantly advancing our understanding of the storm-time Magnetosphere-Ionosphere system and the mid-latitude electrodynamics that occur during active times. This understanding is needed to advance the fundamental science understanding of geomagnetic storms but also has application to practical areas of importance such as communications and navigation for which strong ionospheric electric fields are of paramount concern. This project also continues an informal partnership between APL and the physics department at Augsburg College that consists in providing summer research opportunities for undergraduate students from Augsburg at APL via the JHU/APL Student Summer Internship program. M-I coupling during magnetic storms is one of the important physical processes that affect the upper atmospheric electrodynamics of the polar region. Thus, the research project will contribute to the larger research goals of the International Polar Year Program at NSF.