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

研究人员将利用碟外干涉接收技术为新的阿雷西博高频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，这将需要一个T/R（发射/接收）开关。碟外干涉测量接收器系统将采用小型有源天线阵列，并且在初始模拟滤波之后，采用全数字接收器系统。碟上和碟外接收器系统可以同时使用，从而产生最灵敏的系统。 这一雷达系统将通过增加流星物理学研究的能力来实现新的科学。 最近的发现表明，绝大多数作为雷达流星可见的流星体是碎片，而不仅仅是烧蚀。这个过程是一个重要的纳米可能来源？灰尘？在80-130公里的高度区域，流星消融。该雷达将与阿雷西博的46.8兆赫和430兆赫雷达一起使用，以探索碎裂问题。 综合测量将有助于研究流星尾迹中的无线电波散射机制以及流星在大气中存款重要金属的过程。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。 该仪器还可用作MST（中间层-平流层-对流层）雷达和太阳活动极小期的潜在凌日日冕雷达。 将HF加热器的功能扩展到包括雷达模式将使Arecibo仪表组能够实现许多新的科学。高频雷达将允许直接探测D区加热效应，并可能探测闪电引起的D区电离。 这项工作将通过进一步实现共模多雷达活动和支持正在进行的模型开发工作，为学生参与研究提供新的机会。 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.