论文标题
CO+第一型带发射：Martian上层大气中的CO示踪剂
CO+ first-negative band emission: A tracer for CO in the Martian upper atmosphere
论文作者
论文摘要
最近，成像紫外光谱仪（IUV）在火星上观察到的火星大气层和挥发性进化（Maven）卫星在火星上层大气中观察到Co $^+$ $^+$第一（+$）。我们旨在探索火星上层大气中的光化学过程，该过程驱动了该乐队的发射。开发了一个光化学模型，以研究MARS上层大气层的Co $^+$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $^2σ^+\ rightarrow $ x $^2σ^+$）的激发过程。 CO $ _2 $和CO的数量密度曲线来自两个不同的模型，即MARS气候数据库（MCD）和MARS Global Ionsphere-thermosphere（MGIT）用于确定该频带发射的肢体强度。在MCD和MGIT模型中分别将CO密度提高4和8时，发现模型的CO $^+$第一阴性带肢体强度曲线与IUVS/MAVEN观察一致。在这种情况下，该频段发射的强度通过太阳能光子和光电子的CO的电离显着确定，而CO $ _2 $的分离电离的作用可忽略不计。由于CO是CO $^+$（B $^2σ^+$）的主要来源，因此我们建议观察到的CO $^+$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $^+$一负频段发射强度可用于检索Martian上层气氛中高度150 km的高度。
Recently, Imaging Ultraviolet Spectrograph (IUVS) on-board Mars Atmosphere and Volatile EvolutioN (MAVEN) satellite observed CO$^+$ first-negative band limb emission in the Martian upper atmosphere. We aim to explore the photochemical processes in the Martian upper atmosphere, which drives this band emission. A photochemical model is developed to study the excitation processes of CO$^+$ first-negative band emission (B$^2Σ^+ \rightarrow$ X$^2Σ^+$) in the upper atmosphere of Mars. The number density profiles of CO$_2$ and CO from two different models, viz., Mars Climate Database (MCD) and Mars Global Ionosphere-Thermosphere (MGIT) are used to determining the limb intensity of this band emission. On increasing the CO density by a factor of 4 and 8 in MCD and MGIT models, respectively, the modelled CO$^+$ first-negative band limb intensity profile is found to be consistent with IUVS/MAVEN observation. In this case, the intensity of this band emission is significantly determined by the ionization of CO by solar photons and photoelectrons, and the role of dissociative ionization of CO$_2$ is negligible. Since CO is the major source of the CO$^+$(B$^2Σ^+$), we suggest that the observed CO$^+$ first-negative band emission intensity can be used to retrieve the CO density in the Martian upper atmosphere for the altitudes above 150 km.
