CEDAR: Physics of the Hydrogen Geocorona

CEDAR：氢地冕的物理学

• 批准号: 0535433
• 负责人: Fred Roesler
• 金额: --
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0535433&HistoricalAwards=false
• 关键词: CEDAR; Physics; Hydrogen; Geocorona

Long-term measurements of the geocoronal Balmer-alpha emission are continued at the Pine Bluff Observatory near Madison, WI, and at Kitt Peak, NM using Fabry-Perot interferometers. Unprecedented instrument sensitivity due to low-noise image plane detection allows these geocoronal measurements to be extended to include measurements of the sub-Rayleigh Balmer-beta emission. Due to the dissimilar optical transport properties of these two emissions from the same source, it is possible to extract accurate values of atomic hydrogen (H) density profiles from the upper thermosphere to several thousand kilometers. That atomic H is the neutral source of the topside ionosphere, and can be used by virtue of charge exchange equilibrium to determine the density of atomic oxygen (O) in the upper thermosphere. Once determined, the atomic H altitude profiles are used to determine the vertical flux of H. The long term data base is also used to determine the solar cycle variability of exospheric H, and to explore the possibility of secular variability that relates to changes in whole-atmosphere hydrogenous species abundance that may be changing in concert with methane deposition in the lower atmosphere. High spectral resolution measurements at Pine Bluff are also used to quantify effective temperature near and above the exobase, and to quantify atomic cascade contributions to the Balmer line profiles.

长期测量的地冠巴尔默-α发射继续在松树海崖天文台附近的麦迪逊，威斯康星州，并在基特峰，NM使用法布里-珀罗干涉仪。 前所未有的仪器灵敏度，由于低噪声图像平面检测允许这些geocoronal测量扩展到包括测量的亚瑞利巴耳末-β发射。 由于这两种来自同一来源的发射的光学输运性质不同，因此有可能提取从热层上部到数千公里的原子氢（H）密度分布的精确值。 氢原子是顶部电离层的中性源，可以通过电荷交换平衡来确定上层热层中原子氧（O）的密度。 一旦确定，原子H高度分布被用于确定H的垂直通量。 长期的数据库也被用来确定太阳周期的变化外气层H，并探讨长期的变化，涉及到整个大气中的含氢物种丰度的变化，可能会改变在演唱会与甲烷沉积在低层大气中的可能性。 高光谱分辨率测量松海崖也被用来量化有效温度附近和以上的外底，并量化原子级联贡献的巴耳末线配置文件。