Pickett N B, McFadden J P, Fowler C M, Hanley K G, Benna M
Space Sciences Laboratory Berkeley CA USA.
Goddard Space Flight Center Greenbelt MD USA.
J Geophys Res Space Phys. 2022 Jan;127(1):e2021JA029635. doi: 10.1029/2021JA029635. Epub 2021 Dec 30.
Characterizing C ions in the Martian ionosphere is important for understanding the history of the Martian atmosphere and surface due to its place in understanding carbon escape. Measuring minor ions, like C, which are close in mass to major atmospheric ions, in this case O, is difficult, requiring fitting algorithms and accurate background subtraction. Accurate measurement of these species is essential for understanding chemistry and transport in the ionosphere. In this paper, we use data from the Mars Atmospheric and Volatile EvolutioN SupraThermal And Thermal Ion Composition (MAVEN-STATIC) sensor to report the first C fluxes measured in the Martian magnetotail. We will describe a multistep method of background subtraction as well as fitting routines that are used to extract C fluxes from a 40-orbit subset of STATIC data. Our results show tailward fluxes in both optical shadow and the adjacent sunlit magnetotail at high altitudes ( 3,000 km) and Mars-ward at low altitudes ( 2,000 km) in shadow. These local flux values are similar to estimates of neutral carbon fluxes from photochemical escape. However, total carbon loss comparisons will require a more comprehensive study of integrated C loss over a larger data set from the Martian magnetotail.
由于碳离子在理解火星大气逃逸过程中所起的作用，表征火星电离层中的碳离子对于了解火星大气和表面的历史至关重要。测量质量与主要大气离子（在这种情况下为氧离子）相近的微量离子（如碳离子）很困难，需要拟合算法和精确的背景扣除。准确测量这些物质对于理解电离层中的化学过程和输运至关重要。在本文中，我们使用火星大气与挥发物演化超热和热离子成分（MAVEN - STATIC）传感器的数据，报告了在火星磁尾首次测量到的碳通量。我们将描述一种多步骤的背景扣除方法以及用于从STATIC数据的40个轨道子集中提取碳通量的拟合程序。我们的结果表明，在高海拔（> 3000公里）的光学阴影区和相邻的日照磁尾以及低海拔（< 2000公里）阴影区的磁尾中，都存在向尾通量。这些局部通量值与光化学逃逸产生的中性碳通量估计值相似。然而，要进行总碳损失比较，需要对来自火星磁尾的更大数据集上的综合碳损失进行更全面的研究。
