SGER: A Search for a Hot Oxygen Corona Using High Spectral Resolution OII 732 nm Measurements

该项目评估的命题，即人口的非热O和O+原子普遍存在于高层大气和顶侧电离层。这种“热氧”人口在文献中确定的[O]和[O+]的标度高度来自可见光和紫外线黄昏气辉排放，并通过测量的O+ 732.0纳米光谱特征的热线宽。该项目的目的是通过比较光学和雷达测量结果直接评估中纬度的O+温度。这些任务包括：（1）利用2003年5月在阿雷西博天文台进行的732.0 nm高光谱分辨率测量导出O+温度;（2）利用阿雷西博非相干散射雷达（ISR）技术获得一组新的732.0 nm数据，这些数据与O+温度的同时测量相索引;初步分析2003年5月的数据，要求治疗的混合双峰光谱功能，不表明一个显着的人口热O+的基础上的配置文件宽度。然而，新的天文数据表明，双重分裂比早期的研究确定的要大得多，因此有必要对混合双重分裂的温度进行新的分析。这项研究涉及2003年初秋的一次观测活动，在阿雷西博天文台使用集群仪器同时测量黄昏期间OII 732.0 nm发射、OI 630.0 nm发射和HI 656.3 nm发射的多普勒轮廓。同时ISR测量的O+温度将在天顶和75度的海拔在这个实验期间获得。因此，观测将使用三个法布里-珀罗干涉仪（FPI），两个光度计，一个全天空成像仪和非相干散射雷达（ISR）。结果应提供四个独立的温度测量值：一个来自F2电离层峰值以下（来自OI 630.0 nm剖面），两个来自顶侧电离层阴影终止器附近（来自HI 656.3 nm和OII 732.0 nm剖面），一个来自ISR技术。这项研究广泛影响了通过其他实验和分析技术进行的高层大气和顶部电离层成分研究。顶侧离子组成，来自雷达技术，目前取决于在顶侧可以忽略不计的热O的假设。这一重要性反过来又影响到空间天气对顶侧可靠的H+成分的需求，目前最好的供应方式是雷达技术。

This project evaluates the proposition that a population of non-thermal O and O+ atoms commonly exists in the upper atmosphere and topside ionosphere. This "hot oxygen" population is identified in the literature by scale heights of [O] and [O+] derived from visible and ultraviolet twilight airglow emissions, and by measuring the thermal line width of the O+ 732.0 nanometer spectral feature. The aim of the project is to achieve a direct evaluation of the O+ temperature at mid-latitude by comparing optical and radar measurements. The tasks include: (1) Derivation of O+ temperature from high spectral resolution 732.0 nm measurements made at the Arecibo Observatory in May, 2003, (2) Acquisition of a new set of 732.0 nm data indexed to simultaneous measurements of O+ temperature using the Arecibo Incoherent Scatter Radar (ISR) technique, and (3) A review of previous 7320 nm line profile data. Preliminary analysis of the May 2003 data, demanding treatment of a mixed doublet spectral feature, do not indicate a significant population of hot O+ based on the profile widths. However, new astronomical data suggest that the doublet splitting is significantly larger than earlier research has determined, and a new analysis of temperature derived from the mixed doublet is necessary. The study involves an observational campaign in the early fall of 2003 using clustered instrumentation at the Arecibo Observatory to simultaneously measure the Doppler profiles of the OII 732.0 nm emission, the OI 630.0 nm emission, and the HI 656.3 nm emission during twilight periods. Simultaneous ISR measurements of the O+ temperature will be obtained between the zenith and 75 degrees elevation during this experiment. The observations will thus employ three Fabry-Perot interferometers (FPI), two photometers, an all sky imager, and the incoherent scatter radar (ISR). The results shall provide four independent measures of temperature: one from just below the F2 ionospheric peak (from the OI 630.0 nm profiles), two from near the shadow terminator in the topside ionosphere (from the HI 656.3 nm and OII 732.0 nm profiles), and one from the ISR technique. This research broadly impacts upper atmospheric and topside ionospheric composition research by other experimental and analytical techniques. The topside ion composition, derived from radar techniques, currently depends upon the assumption of negligible hot O in the topside. The significance in turn impacts the space weather need for reliable H+ composition in the topside, which are currently best supplied by radar techniques.