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

MRI：开发用于研究电离层无线电发射和结构的高分辨率无线电成像系统

• 批准号: 1428596
• 负责人: Brett Isham
• 金额: $ 43.02万
• 依托单位: Inter American University of Puerto Rico San Juan
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2020-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1428596&HistoricalAwards=false
• 关键词: MRI; Development; Resolution; Radio; Imaging

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.

电离等离子体构成了宇宙中99%的可直接观测物质，更好地了解附近空间等离子体中的湍流可以应用于许多空间和天体物理环境，以及磁航天器辐射屏蔽，推进（离子发动机，太阳帆），改善空间对地面通信和导航（GPS）链接，设备制造和聚变能源发电等技术问题。在波多黎各的阿雷西博天文台，一个新的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。 该奖项旨在开发六元中高频（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）对相对窄波束内产生的无线电发射进行成像和光谱及时间研究在电离层无线电波相互作用实验期间，新的阿雷西博天文台发射机（约10度全宽）（2）在波多黎各的卡伊用高频雷达进行的方位角无线电发射观测和多个双基地雷达观测;（3）在卡伊高频雷达的宽发射波束范围内对电离层进行无线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两次，每次约两周，因此届时将使用临时现场进行数千米规模的成像。至少在最初，还将使用临时现场进行20公里至100公里的间距。在其他时候，该阵列将设在波多黎各阿瓜迪利亚的美洲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）将对高频相互作用区域的受激无线电发射（SEE）结构进行成像，目的是确定许多SEE光谱特征相对于地磁场的源区的确切几何形状。该阵列还将显示SEE的偏振是否在光谱特征之间变化。辐射的几何和偏振特性的无线电图像有望揭示辐射物理学的新细节。波多黎各美洲大学的Bayamon和Aguadilla校区是私立的，主要是本科院校，几乎所有的西班牙裔学生，大多数是低收入家庭的学生。将要开发的仪器将提高Interamerican大气、空间和无线电研究基础设施的整体能力，包括正在开发的强调大气和空间研究的研究生课程。