EAGER: Adapting the New Arecibo On-Dish High Frequency (HF) Transmitter System to Radar Mode

研究人员将使用天线外干涉接收技术为新的阿雷西博高频（HF）电离层加热设施开发雷达能力。他们还将探索使用碟上接收模式，这将需要T/R（发送/接收）开关。非碟形干涉接收系统将采用小型有源天线阵列，在初始模拟滤波后，采用全数字接收系统。两种接收系统都可以同时使用，产生最灵敏的系统。该雷达系统将通过增加流星物理研究的能力，使新科学成为可能。最近的发现表明，绝大多数以雷达流星的形式可见的流星体都是碎片，而不是简单地消融。这一过程可能是重要纳米粉尘的来源。在海拔80-130公里的地区，流星会消融。该雷达将与阿雷西博的46.8兆赫和430兆赫雷达一起用于探测碎片。这些综合测量将有助于研究流星轨迹中的无线电波散射机制，以及流星在大气中沉积重要金属的过程。其他重要的科学领域包括研究中纬度扩展f，零星e不稳定性，准周期回波（QPE）结构，低空准周期回波（LQPE）结构，以及与闪电相关的d区电离增强。仪器也可以找到应用作为MST（中间层-平流层-对流层）雷达和潜在的过境日冕雷达在太阳极小期。将高频加热器功能扩展到雷达模式，将使Arecibo仪表集群能够实现许多新的科学研究。高频雷达将允许直接探测d区热效应，并可能探测到闪电引起的d区电离。这项工作将通过进一步实现共模多雷达运动和支持正在进行的模型开发工作，为学生的研究参与提供新的机会。本科生将参与构建和部署该系统，该系统将提供给所有用户社区，包括来自合作机构的学生。

The investigators will develop a radar capability for the new Arecibo high frequency (HF) ionospheric heating facility using off-dish interferometric receive techniques. They will also explore using an on-dish receive mode that would require a T/R (transmit/receive) switch. The off-dish interferometric receiver systems would employ small arrays of active antennas and, after the initial analog filtering, a fully digital receiver system. Both the on and off-dish receiver systems could be used simultaneously yielding the most sensitive system. This radar system will enable new science by adding capabilities to conduct studies of meteor physics. Recent discoveries have shown that the vast majority of meteoroids visible as radar meteors fragment rather than simply ablating. This process is a likely source of important nanometer ?dust? in the 80-130 km altitude region where meteors ablate. The radar would be used in conjunction with the 46.8 MHz and 430 MHz radars at Arecibo to explore fragmentation. The combined measurements would allow studies of the radiowave scattering mechanism in meteor trails, and the processes whereby meteors deposit important metals in the atmosphere. Other important science areas include studies of mid-latitude spread-F, sporadic-E instabilities, quasi-periodic echo (QPE) structures, low-altitude quasi-periodic echoes (LQPE) structures, and the D-region ionization enhancements associated with lightning. The instrument could also find application as an MST (Mesospheric-Stratospheric-Tropospheric) radar and as a potential transit solar corona radar at solar minimum. Extending the HF heater capabilities to include a radar mode will enable much new science from the Arecibo instrument cluster. The HF-radar will allow direct probing of D-region heating effects, and possibly detection of lightning-induced D-region ionization. The effort will provide new opportunities for student research involvement by further enabling common-mode multi-radar campaigns and by supporting on-going model development efforts. Undergraduate students will be involved in building and fielding the system that will be available to all user communities, including students from collaborating institutions.