The precipitation of energetic neutral atoms, produced through charge exchange collisions between solar wind ions and thermal atmospheric gases, is investigated for the Martian atmosphere. Connections between parameters of precipitating fast ions and resulting escape fluxes, altitude-dependent energy distributions of fast atoms and their coefficients of reflection from the Mars atmosphere, are established using accurate cross sections in Monte Carlo simulations. Distributions of secondary hot atoms and molecules, induced by precipitating particles, have been obtained and applied for computations of the non-thermal escape fluxes. A new collisional database on accurate energy-angular dependent cross sections, required for description of the energy-momentum transfer in collisions of precipitating particles and production of non-thermal atmospheric atoms and molecules, is reported with analytic fitting equations. 3D Monte Carlo simulations with accurate energy-angular dependent cross sections have been carried out to track large ensembles of energetic atoms in a time-dependent manner as they propagate into the Martian atmosphere and transfer their energy to the ambient atoms and molecules. Results of the Monte Carlo simulations on the energy-deposition altitude profiles, reflection coefficients, and time-dependent atmospheric heating, obtained for the isotropic hard sphere and anisotropic quantum cross sections, are compared. Atmospheric heating rates, thermalization depths, altitude profiles of production rates, energy distributions of secondary hot atoms and molecules, and induced escape fluxes have been determined.
Oxygen isotope fractionation in the Martian atmosphere induced by CO$_2$ photolysis and O$_3$ formation
Earth-Life Science Institute, Institute of Science Tokyo（地球生命研究所，东京科学大学）；Department of Earth and Space Sciences, University of Washington（华盛顿大学地球与空间科学系）；Department of Geophysics, Graduate School of Science, Tohoku University（东北大学理学研究科地球物理学科）；Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo（东京大学前沿科学研究生院复杂科学与工程系）；Instituto de Astrofísica de Andalucía, CSIC（安达卢西亚天体物理研究所，西班牙国家科学研究委员会）；Research Center for Advanced Science and Technology, The University of Tokyo（东京大学先进科学技术研究中心）；Department of Earth and Planetary Sciences, School of Science, Institute of Science Tokyo（东京科学大学理学院地球行星科学系）；Faculty of Environment and Information Studies, Keio University（庆应义塾大学环境信息学部）
Kelvin-Helmholtz vortices in the Martian +E hemisphere downstream of crustal magnetic anomalies
University of Science and Technology of China（中国科学技术大学）；The University of Hong Kong（香港大学）；National Space Science Center, Chinese Academy of Sciences（中国科学院国家空间科学中心）；Harbin Institute of Technology, Shenzhen（哈尔滨工业大学（深圳））；Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）
Escape and evolution of Mars' CO2 atmosphere: Influence of suprathermal atoms
用蒙特卡罗模型，我们调查了火星大气中的热氧和碳的逃逸在其历史上的四个时间点对应于1，3，10和20倍，目前的太阳EUV通量。我们研究和讨论了热层中热氧和碳原子的不同来源以及它们随着EUV通量的变化而变化的重要性。由于更高的EUV通量导致的更高密度而导致的生产率的增加与热层的膨胀和相应的碰撞增加相竞争。我们发现，由于光解离的逃逸随EUV能级的增加而增加。然而，对于通过一些其他反应的逃逸，例如~ O $_2^+$的解离复合，这仅在EUV水平达到当前EUV通量的10倍之前是真实的，并且然后速率开始降低。此外，我们的研究结果表明，火星在诺亚纪末期不可能有稠密的大气层，因为这样的大气层直到今天才能够逃逸。在前诺亚时代，大部分的岩浆海洋和火山活动相关的脱气CO $_2$大气可能已经失去了热，直到诺亚时代，当非热损失过程，如超热原子逃逸成为主导。因此，早期的火星在前诺亚纪时期可能是炎热潮湿的，在行星起源后的前3亿年期间，表面CO $_2$压力大于1巴。
Characterizing the current systems in the Martian ionosphere
Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences（中国科学院地质与地球物理研究所）；College of Earth and Planetary Sciences, University of Chinese Academy of Sciences（中国科学院大学地球与行星科学学院）；School of Space and Environment, Beihang University（北京航空航天大学空间与环境学院）；Department of Earth Sciences, ETH Zurich（苏黎世联邦理工学院地球科学系）；Swedish Institute of Space Physics（瑞典空间物理研究所）；Center for Space Physics and Department of Astronomy, Boston University（波士顿大学空间物理中心暨天文学系）；Fudan University（复旦大学）；The Shanghai Institute for Mathematics and Interdisciplinary Sciences（上海数学与交叉学科研究院）；Planetary Environmental and Astrobiological Research Laboratory, School of Atmospheric Sciences, Sun Yat-sen University（中山大学大气科学学院行星环境与天体生物学研究实验室）
Simultaneous Mars-orbit observations reveal Kelvin-Helmholtz instability-driven bulk atmospheric ion escape
Boston University（波士顿大学）；Institute for Advanced Study, Princeton（普林斯顿高等研究院）；Catholic University of America（美利坚天主教大学）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；University of Iowa（爱荷华大学）；University of Colorado（科罗拉多大学）；University of California, Berkeley（加州大学伯克利分校）
