Energy transfer in O collisions with He isotopes and Helium escape from Mars
Energy transfer in O collisions with He isotopes and Helium escape from Mars
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DOI：
10.1029/2010gl045763
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发表时间：
2010-12
影响因子：
5.2
通讯作者：
Stefano Bovino;Peng Zhang;F. Gianturco;Alexander Dalgarno;V. Kharchenko
中科院分区：
文献类型：
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作者：
Stefano Bovino;Peng Zhang;F. Gianturco;Alexander Dalgarno;V. Kharchenko
报告了火星上热氧原子和大气氦气之间能量转移碰撞的准确数据。用量子力学方法计算了O（3P）和O（1D）原子与氦气弹性碰撞的各向异性截面，发现它们惊人地相似。截面，计算与氦同位素，3He和4He的碰撞，已被用来构建描述热氧原子的能量弛豫的玻尔兹曼方程的内核。计算的O+He碰撞的能量转移率已被用来评估从火星大气逃逸的He原子的通量。大气层主要负责生产的他逃逸通量确定。我们的研究结果表明，散射截面的强角各向异性增加了轻原子的碰撞弹射，是至关重要的，他从火星，金星和地球逃逸的评价。
Accurate data on energy‐transfer collisions between hot oxygen atoms and the atmospheric helium gas on Mars, are reported. Anisotropic cross sections for elastic collisions of O(3P) and O(1D) atoms with helium gas have been calculated quantum mechanically and found to be surprisingly similar. Cross sections, computed for collisions with both helium isotopes, 3He and 4He, have been used to construct the kernel of the Boltzmann equation describing the energy relaxation of hot oxygen atoms. Computed rates of energy transfer in O+He collisions have been used to evaluate the flux of He atoms escaping from the Mars atmosphere. Atmospheric layers mostly responsible for production of the He escape flux are identified. Our results demonstrate that strong angular anisotropy of scattering cross sections increases the collisional ejection of light atoms and is critical in the evaluation of He escape from Mars, Venus and Earth.