MRI: Development of a High Resolution Radio Imaging System for the Study of Ionospheric Radio Emissions and Structure

电离等离子体占宇宙中直接可观测物质的99%，更好地了解附近空间等离子体的湍流可以应用于许多空间和天体物理环境，以及诸如磁性航天器辐射屏蔽，推进（离子发动机，太阳帆），改善空间对地通信和导航（GPS）链路，设备制造和聚变能产生等技术问题。波多黎各阿雷西博天文台的一台新型高功率高频发射机提供了以一种精心控制的方式研究电离层等离子体的机会。该合同用于开发六元中高频（MF/HF， 0.3至30 MHz）成像无线电阵列。该阵列将有三个主要用途：(1)在电离层无线电波相互作用实验（加热运动）期间，对新阿雷西博天文台发射机相对较窄的波束（全宽约10度）内产生的无线电发射进行成像、光谱和时间研究；(2)波多黎各Cayey地区高频雷达斜角射电发射观测和多台双基地雷达观测；(3) Cayey地区高频雷达宽发射波束内电离层定向射电发射观测和雷达成像研究。阿雷西博天文台的高频活动预计每年进行两次，每次约两周，因此届时将使用临时现场站点进行多公里尺度的成像。至少在最初阶段，还可以使用临时现场站点进行20公里至100公里的间隔。在其他时候，天线阵将设在波多黎各阿瓜迪拉泛美大学校园的一个永久地点，在那里将使用10米至300米的天线间距。12公里阵列（阵列1）将从高频相互作用区对受激射电发射（SEE）的结构进行成像，目的是确定许多SEE光谱特征的源区域相对于地磁场的精确几何形状。该阵列还将显示SEE的偏振是否在光谱特征之间变化。发射的几何和偏振特性的射电图像有望揭示发射物理的新细节。波多黎各泛美大学的巴亚蒙和阿瓜迪亚校区是私立的，主要是本科院校，几乎所有的学生都是西班牙裔，主要是低收入家庭的学生。将要开发的仪器将提高泛美航空公司大气、空间和无线电研究基础设施的总体能力，包括正在发展的强调大气和空间研究的研究生项目。

Ionized plasmas make up 99% of the directly observable matter in the universe, and a better understanding of turbulence in nearby space plasmas can be applied to many space and astrophysical environments, and to technological problems such as magnetic spacecraft radiation shielding, propulsion (ion engine, solar sail), improving space-to-ground communication and navigation (GPS) links, device fabrication, and fusion energy generation. A new high-power, high-frequency transmitter at the Arecibo Observatory in Puerto Rico offers opportunities to study ionospheric plasmas in a carefully controlled way. This award is for the development of a six-element medium and high-frequency (MF/HF, 0.3 to 30 MHz) imaging radio array. There will be three primary uses of the array: (1) Imaging and spectral and temporal study of radio emissions generated within the relatively narrow beam (about 10-deg full width) of the new Arecibo Observatory transmitter during ionospheric radio wave interaction experiments (heating campaigns); (2) Oblique-angle radio emission observations and multiple bistatic radar observations with an HF radar in Cayey, Puerto Rico; and (3) Direction-finding radio emission observations and radar imaging studies of the ionosphere within the wide transmitter beam of the HF radar in Cayey. Arecibo Observatory HF campaigns are anticipated to be twice a year for about two weeks each, so imaging with multi-kilometer-scale spacings would be done then, using temporary field sites. 20-km to 100-km spacings would also be done using temporary field sites, at least initially. At other times the array would be located at a permanent site at the Interamerican University campus in Aguadilla, Puerto Rico, where 10-m to 300-m antenna spacings would be used. The 12-km array (array 1) would image the structure of stimulated radio emissions (SEE) from the HF interaction region with the goal of determining the exact geometries of the source regions of the many SEE spectral features with respect to the geomagnetic field. The array would also show whether or not the polarization of SEE varies between spectral features. Radio images of the geometric and polarization properties of the emissions promise to reveal new details of the physics of the emissions. The Bayamon and Aguadilla campuses of Interamerican University of Puerto Rico are private, primarily undergraduate institutions with nearly all Hispanic, mostly low-income students. The instruments to be developed would enhance the overall capabilities of the atmospheric, space, and radio research infrastructure at Interamerican, including the ongoing development of a graduate program emphasizing atmospheric and space research.