The Arecibo High Frequency (HF) Facility: An Instrument to Study Ionospheric Physics

这是一个重建阿雷西博天文台高频（HF）设施的奖项，使用了300米望远镜盘上的创新天线系统。 阿雷西博天文台从缅因州一个退役的超视距（OTH）雷达设施获得了多余的发射机，并从海军研究办公室和空军国防大学研究仪器计划（DURIP）科学研究办公室获得了资金。 该奖项支持在天文台建造设施所需的努力的平衡。 高频设施对于在理解强大的高频无线电波与电离层等离子体之间的相互作用方面不断取得进展以及在高层大气学的若干方面取得新发现至关重要。 该设施将包括一个高频天线系统，为300米的碟形天线供电，高频发射机，以及一个电力传输系统。 世界上现有的高频设施都没有阿雷西博的诊断能力和地球物理环境的组合。 这包括在阿雷西博的非常敏感的非相干散射雷达，以及一套支持光学仪器，和一个具有安静稳定的背景电离层的中纬度磁位置。 这种独特的组合是研究相互作用的基本物理过程的理想选择。在1998年9月被乔治飓风摧毁之前，阿雷西博高频设施位于观测站东北部，靠近波多黎各海岸。 由于波多黎各政府改变了土地使用政策，不可能在该地区重建，因此最实际和最便宜的解决办法是建造一个具有新功能的设施，利用天文台300米的主盘作为反射天线。 OTH设施的剩余发射机处于完美状态，易于操作。 它们将连接到位于碟形表面中心附近的馈源，并传输到位于平台下方的丝网副反射器（卡塞格伦）。 然后，该反射器照亮主盘以产生高增益HF信号。 这种组合将为各种实验提供所需的电力，包括在更高频率下产生人造气辉和加速电子。 与过去一样，新设施将支持来自许多大学的博士指导研究生和本科生研究计划。 研究人员将在天文台一流的游客设施中增加一个新的展览，以促进对高层大气学的理解以及地面观测对了解我们的空间和大气环境的重要性。 在阿雷西博的HF研究将高空物理学，空间物理学，等离子体物理学和教育结合在一起，使NSF的战略计划能够有效实施，以增强多样性，为社区提供最先进的基础设施，并提供机会来推进科学和工程的发现和理解。

This is an award to rebuild the Arecibo Observatory High Frequency (HF) facility using an innovative antenna system over the 300m telescope dish. The Arecibo Observatory has obtained surplus transmitters from a decommissioned Over the Horizon (OTH) radar facility in Maine, and has obtained funding from both the Office of Naval Research and the Air Force Office of Scientific Research Defense University Research Instrumentation Program (DURIP). This award supports the balance of the effort needed to construct the facility at the Observatory. The HF Facility is essential for continuing progress toward the understanding of the interaction between a powerful HF radio wave and the ionospheric plasma and for making new discoveries in several aspects of aeronomy. The facility will consist of an HF antenna system to feed the 300 m dish, HF transmitters with a building to house them, and a power transmission system. None of the existing HF facilities in the world has Arecibo's combination of diagnostic capabilities and geophysical environment. This includes the extraordinarily sensitive incoherent scatter radar at Arecibo, as well as a suite of supporting optical instrumentation, and a magnetic mid-latitude location with a quiet stable background ionosphere. This unique combination is ideal to study the underlying physical processes of the interaction in full detail. Until its destruction in September 1998 by Hurricane Georges, the Arecibo HF facility was located to the northeast of the Observatory near the coast of Puerto Rico. Since it is not possible to rebuild in that area due to policy changes in land use by the Puerto Rican Government, the most practical and least expensive solution is to construct a facility with new capabilities using the 300 meter main dish of the Observatory as a reflecting antenna. The surplus transmitters from the OTH facility are in perfect condition and easy to operate. They will be connected to feeds located near the center of the surface of the dish and transmit to a wire mesh sub-reflector (Cassegrain) located well below the platform. This reflector then illuminates the main dish to make a high gain HF signal. The combination will provide the power needed for a variety of experiments, including the production of artificial airglow and accelerated electrons at the higher frequency. As in the past, the new facility will support PhD directed graduate and undergraduate research programs from many universities. The investigators will add a new exhibit to the observatory's superb visitor facility, for promoting the understanding of aeronomy and the importance of ground-based observations for understanding our space and atmospheric environment. HF studies at Arecibo tie together aeronomy, space physics, plasma physics and education in a unique combination that allows for an effective implementation of NSF's strategic plan for enhancing diversity, making state of the art infrastructure available to the community, and providing opportunities to advance discovery and understanding of science and engineering.