SGER: Ground-based Optical Detection of the Ring Current

调查人员将对用于环流降水地面监测的光学技术进行概念验证探索性研究，最终可能导致建立一个全球分布式测光网络。这项研究将侧重于利用地面光学观测确定环电流的组成、形态和演变的可行性。观测将使用一种新型的望远镜阵列和光度计进行，该望远镜阵列和光度计将在夏威夷运行六个月，以收集至少一次重大磁暴的数据。夏威夷位于高能中性原子（ENA）降水增强的地磁纬度，是进行初步调查的最佳光学位置。近年来，在理解地磁暴物理学方面取得了重要进展。许多建模和观测研究的目的是解释磁气圈近地区域（称为环电流）在风暴期间的质量和能量变化。虽然诸如热层电离层中间层能量学和动力学（TIMED）和磁层顶至极光全球探测成像仪（IMAGE）等卫星的出现为环电流的全球测量提供了极好的数据库，但卫星一般都很昂贵，每次通过只能对特定区域进行一次测量，而且寿命有限。地面光学仪器是卫星空间气象监测的一种有吸引力的补充替代方法。虽然地面环电流相关的光发射已经观察到在过去，这项研究将首次验证的可行性，连续监测环电流从地面和测试在各种波长和现场测量的O+和H+的数量和能量密度观测到的排放之间的关系。研究人员将通过结合地面测量和卫星测量，量化光学可观测量和现场粒子测量之间的关系。这种测量现在特别及时，而IMAGE和POLAR卫星仍在轨道上提供天基环电流核查。如果得到肯定的结果，就可以利用分布在纬度和经度上的地面光学仪器网络来测量环流的天气和气候，就像气象站测量地球大气的气候和天气一样。该项目的最终目标是确定地基光学测量是否可以用于系统地探测环电流降水，并使用这些测量来跟踪强磁暴期间的环电流成分、形态和演变。

The investigators will conduct a proof-of-concept exploratory study of an optical technique for ground-based monitoring of ring current precipitation that could ultimately lead to a global distributed photometric network. The study will focus on the feasibility of using ground-based optical observations to determine ring current composition, morphology, and evolution. The observations will be made with a novel telescopic array and photometer to be operated in Hawaii for six months in order to gather data from at least one major magnetic storm. Hawaii is at a geomagnetic latitude of enhanced Energetic Neutral Atom (ENA) precipitation and is an optimal optical location for this initial investigation. Important advances have been made in recent years in understanding the physics of geomagnetic storms. Numerous modeling and observational studies have been aimed at explaining the storm-time changes in mass and energy of the near-Earth region of the magnetosphere known as the ring current. While the advent of satellites such as Thermosphere Ionosphere Mesosphere Energetics and Dynamic (TIMED) and Imager for Magnetopause to Aurora Global Exploration (IMAGE) provide an excellent database for global measurements of the ring current, satellites in general are costly, are able to make measurements of only a particular region once per pass, and have a limited lifetime. Ground-based optical instruments pose an attractive and complementary alternative to satellite-based monitoring of space weather. Although ground-based ring-current-related optical emissions have been observed in the past, this study will verify for the first time the feasibility of continuously monitoring the ring current from the ground and test the relationship between emissions observed at various wavelengths and in situ measurements of O+ and H+ number and energy density. The investigators will quantify the relationships between optical observables and in situ particle measurements by combining ground-based measurements with satellite measurements. Such measurements are particularly timely now, while the IMAGE and POLAR satellites are still in orbit to provide space-based ring current verification. An affirmative result would open the applicability of a network of ground-based optical instruments distributed in both latitude and longitude to measure the weather and climate of the ring current, much like meteorological stations measure the climate and weather of the terrestrial atmosphere. The final goal of this project is to determine whether groundbased optical measurements can be used to systematically detect ring current precipitation and to use these measurements to track ring current composition, morphology, and evolution during strong magnetic storms.