Collaborative Research: Laboratory Measurements of O and N2 Ultraviolet (UV) Cross Sections by Particle Impact for Remote Sensing of Thermosphere O/N2 Variation

合作研究：通过粒子撞击对 O 和 N2 紫外线 (UV) 截面进行实验室测量，以遥感热层 O/N2 变化

基本信息

批准号：
1853618
负责人：
Richard Eastes
金额：
$ 19.76万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-01 至 2022-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1853618&HistoricalAwards=false
关键词：
Collaborative Research Laboratory Measurements N2

项目摘要

This award would advance the capabilities for UV remote sensing by targeting a laboratory goal, which is centered on the determination of the UV emission cross sections (Qem) needed for remote sensing observations of the Earth's dayglow. In the dayglow a unique signature of the O/N2 density ratio, from satellite-based UV observations, comes from measuring the intensity ratio of the OI (135.6 nm (3P2- 5So2)) and N2 Lyman-Birge-Hopfield (LBH) band (125-250 nm) emissions. This O/N2 density ratio is a key to understanding the ionosphere and thermosphere composition changes on a global scale under all geomagnetic conditions. However, the total emission cross sections of these two sets of spectral transitions have not been measured. Each of these two total emission cross sections is a sum of a direct excitation emission cross section and a cascade cross section. The cascade cross sections are about 30-50% of the total cross section. As the column density ratio O/N2 plays a key role in Space Weather studies, accurate absolute measurements of Qem for both OI and LBH emissions are vital for explaining both the magnitude and temporal evolution of thermosphere composition (O/N2) changes. Similarly, the energetic proton (H+) and H atom impact laboratory measurements of Qem needed for auroral remote sensing are inadequate. The main focus of this is two-fold. One graduate student (UCF) and one undergraduate student would be supported in this effort.The first goal of the award project would be to measure the absolute direct electron, H+, and H impact Qem for both the LBH band between 125 nm to 250 nm and OI (3P2--5So2) at 135.6 nm from their emission thresholds to 500 eV by electron-impact, to 50 keV by H+ and H atom impact, using the team's experimental facilities located at Caltech/JPL. The team would also measure at the University of Colorado the cascade processes from these upper states. Aeronomers at the University of Central Florida (UCF) and Computational Physics Inc. (CPI) would model the remote sensing data using two classic particle transport codes that are paramount to the US space mission: AURIC and GLOW.

该奖项将通过针对实验室目标来推动紫外遥感的能力，该目标以确定地球日光遥感观测所需的紫外线排放横截面（QEM）为中心。在日光下，来自基于卫星的紫外线观测的O/N2密度比的独特签名来自测量OI（135.6 nm（3p2-5SO2））和N2 Lyman-Birge-Hopfield（LBH）带的强度比（125-250 nm）排放。该O/N2密度比是理解在所有地磁条件下全球尺度上电离层和热层组成变化的关键。但是，尚未测量这两组光谱跃迁的总发射横截面。这两个总发射横截面中的每一个都是直接激发发射横截面和级联横截面的总和。级联横截面约为总横截面的30-50％。由于O/N2的色谱柱密度比在太空天气研究中起关键作用，因此对OI和LBH排放的QEM的准确测量对于解释热层组成（O/N2）变化的大小和时间演化至关重要。同样，高能质子（H+）和H原子冲击实验室对极光遥感所需的QEM的测量不足。这是两个方面的重点。一名研究生（UCF）和一名本科生将在这项工作中得到支持。使用该团队的实验设施位于CalTech/JPL，在135.6 nm处从其排放阈值到500 eV到500 eV到500 eV，到500 eV到500 eV。该团队还将在科罗拉多大学衡量这些上州的级联流程。中央佛罗里达大学（UCF）和计算物理公司（CPI）的空气仪将使用两个对美国太空任务至关重要的经典粒子传输代码对遥感数据进行建模：AURIC和GLOW。