Collaborative Research: RUI--Intermediate Scale Structures in the Auroral Oval and the Ionospheric Trough

该项目旨在研究在极光赤道边缘和中纬度槽发育的中尺度不规则现象的发生和分布。将利用美国东北部六个无源无线电信标接收器组成的网络来建立一个数据库，然后对该数据库进行查询，以确定中间比例尺结构的形态。一个特别的目标是确定结构的纬向变化与源区（如极光椭圆区或槽区）和地磁活动水平的关系。该数据库包括总电子含量（TEC）、相位闪烁和TEC波动率的测量数据，这些数据将通过监测低地球轨道卫星在150兆赫和400兆赫的无线电信标传输获得。将用于调查的接收器中有五个已经存在；该项目寻求在纽约州北部建立第六个接收人。接收机是相干电离层多普勒接收机（CIDR），该项目下建立的6个CIDR网络将构成东北CIDR阵列（NECA）。四名受助人分别是康奈尔大学、纽约州立大学奥内昂塔分校、锡耶纳学院和麻省理工学院。它们分布在约400公里的经度上，地磁纬度约为北纬54度。这种阵列配置可以测量中尺度等离子体不规则性的发生和空间分布特征，范围从100米到30公里。南部CIDR已经部署在Wallops岛，大约在南纬4度，第六个CIDR将于2007年秋天在纽约北部的Adirondacks（北纬2度）建立。来自接收机的数据将用于确定观测到的闪烁和波动的大致高度。一旦确定了大致的高度，观测到的闪烁就可以定位在地磁纬度和经度上，以及相对于极光椭圆、电离层槽和风暴增强密度（SED）羽流的位置上。该项目的广泛影响包括教育和社会两方面。这项调查将有助于确定具体影响地球和近地空间技术的空间天气过程的原因。电离层的不规则会在无线电通信和导航系统中产生闪烁，并在雷达信号中产生“杂波”。这种系统在航空旅行行业中无处不在。由于在极光椭圆和电离层槽附近有越来越多的航空旅行，这些区域等离子体不规则现象的形态和发生不仅具有科学价值，而且具有社会意义。将建立一个中央数据库来储存所有非洲经委会的观测资料，这些资料将免费和公开提供。该项目将由本科生参与调查的各个方面，包括数据采集、存档、处理和质量控制。这将使参与的学生熟悉仪器和数据，并发展他们的科学和技术能力。

The project aims to investigate the occurrence and distribution of intermediate scale irregularities that develop on the equatorward edge of the aurora and in the midlatitude trough. A network of six passive radio beacon receivers in the northeast United States will be used to assemble a database which will then be interrogated to establish the morphology of the intermediate scale structures. A particular goal is to determine the relation of the zonal variations of the structures to the source region, such as the auroral oval or the trough, and to the level of geomagnetic activity. The database comprises measurements of the total electron content (TEC), phase scintillations, and the rate of TEC fluctuations which will be obtained by monitoring radio beacon transmissions at 150 MHz and 400 MHz from low-Earth-orbiting satellites. Five of the receivers to be used in the investigation already exist; the project seeks to establish a sixth receiver in upstate New York. The receivers are Coherent Ionospheric Doppler Receivers, or CIDRs, and the network of six CIDRs established under this project will constitute the North East CIDR Array (NECA). The locations of four of the receivers are Cornell, SUNY-Oneonta, Siena College, and MIT. These are distributed over about 400 km of longitude at a geomagnetic latitude of ~54 degrees north. This array configuration enables measurements of the occurrence and spatial distribution characteristics of intermediate scale plasma irregularities, ranging in size from 100 m to 30 km. A southern CIDR has been deployed at Wallops Island, at roughly 4 degrees southern magnetic latitude, and a sixth CIDR will be established in the Adirondacks of Northern New York (2 degrees north magnetic latitude) in the fall of 2007. Data from the receivers will be used to determine the approximate altitude of observed scintillations and fluctuations. Once the approximate altitude has been determined, the observed scintillation can be located in geomagnetic latitude and longitude, as well as in position relative to the auroral oval, the ionospheric trough, and the storm enhanced density (SED) plumes. The broader impacts of the project are both educational and societal. The investigation will contribute to the determination of causes of space weather processes that specifically impact technologies on Earth and in near-Earth space. Ionospheric irregularities produce scintillation in radio communication and navigation systems and generate "clutter" in radar signals. Such systems are ubiquitous in the air travel industry. Since there are increasing levels of air travel near the auroral oval and ionospheric trough, the morphology and occurrence of plasma irregularities in these regions has societal implications as well as scientific merit. A central database will be established to store all the NECA observations which will be freely and publicly available. The project will involve undergraduates in all aspects of the investigation, including data acquisition, archiving, processing, and quality control. This will enable participating students to become familiar with the instrumentation and data as well as develop their scientific and technological competence.