CEDAR: A Study of the Coupled Thermosphere, Exosphere and Hot Oxygen Geocorona

CEDAR：热层、外逸层和热氧地冕耦合的研究

• 批准号: 0437343
• 负责人: John Noto
• 金额: --
• 依托单位: Scientific Solutions Incorporated
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-11-15 至 2009-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0437343&HistoricalAwards=false
• 关键词: CEDAR; Study; Coupled; Thermosphere; Exosphere

This project investigates non-thermal populations of neutral atomic hydrogen, metastable helium, and oxygen ions that are the manifestation of ion-neutral coupling between the thermosphere, ionosphere, and exosphere. Fabry-Perot interferometers (FPI) at the Arecibo Observatory are used to directly sample the velocity distributions of O+, metastable He, and H above the F-region peak, using measurement and analyses of the infrared (IR) 732 nm, 108.3 nm, and optical 656.3 nm airglow emission line profiles respectively. The 430 MHz incoherent scatter radar (ISR) is operated simultaneously, providing the thermal, compositional, and dynamic state of the coupled topside ionosphere. The observations will help characterize thermal and dynamical coupling between the few neutral and ions species populating the upper atmosphere. Resolution of persistent uncertainties, including energy balance between the thermosphere and topside ionosphere, and the atmospheric escape of light gases, demands a quantitative assessment of the role of non-thermal populations in the structure and dynamics of the coupled regions. The data will be used to infer the abundances and velocity distributions of non-equilibrium particles between 300 and 1000 km altitude and consequently characterizes the various physical, chemical, and dynamic processes that the coupled species undergo. Questions that will be addressed by quantification of energetic populations include a controversial heat-balance discrepancy between F-region temperature and neutral O density calculated by semi-empirical models. The temperature sensitivity of ion-neutral interaction may contribute to sustenance of the nighttime F-region, which is only loosely, ascribed to downward transport from the plasmasphere at night. A central objective of this project is a long-overdue upgrade of the Arecibo Optical Laboratory. These upgrades benefit and invigorate research using the nested instrumentation at Arecibo. Space weather and global change research are broadly impacted by improved modeling based on well constrained H and H+ topside abundances.

这个项目研究了中性原子氢、亚稳态氦和氧离子的非热布居，这些离子是热层、电离层和外部层之间离子-中性耦合的表现。利用阿雷西博天文台的法布里-珀罗涉仪，通过测量和分析红外(IR)732 nm、108.3 nm和光学656.3 nm气辉发射线轮廓，直接采样F区峰值以上的O+、亚稳态He和H的速度分布。430 MHz非相干散射雷达(ISR)同时工作，提供耦合的顶部电离层的热、成分和动态信息。这些观测将有助于描述高空大气中少数中性和离子物种之间的热耦合和动力学耦合。要解决持续存在的不确定因素，包括热层和上层电离层之间的能量平衡，以及轻气体在大气中的逸出，需要对非热群体在耦合区域的结构和动态中的作用进行定量评估。这些数据将被用来推断300至1000公里高度之间非平衡粒子的丰度和速度分布，从而表征耦合物种经历的各种物理、化学和动力学过程。用半经验模型计算的F区温度和中性氧密度之间的热平衡差异是有争议的，这些问题将通过对高能种群的量化来解决。离子-中性相互作用的温度敏感性可能有助于夜间F区的维持，这只是松散地归因于夜间等离子体层的向下输送。该项目的一个中心目标是对阿雷西博光学实验室进行拖延已久的升级。这些升级使阿雷西博使用嵌套仪器的研究受益，并为研究注入活力。空间天气和全球变化研究受到基于H和H+上层丰度的改进模型的广泛影响。