Curved Trajectory Effect on Charge‐Exchange Collision at Ionospheric Temperatures
Curved Trajectory Effect on Charge‐Exchange Collision at Ionospheric Temperatures
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DOI：
10.1029/2021ja029612
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发表时间：
2022-01
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影响因子：
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通讯作者：
A. Ieda
中科院分区：
文献类型：
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作者：
A. Ieda
离子和中性粒子之间的碰撞是地球电离层的一个基本特征。这种离子-中性碰撞通常是由中性粒子的极化引起的。如果粒子对是母体，如氧原子及其离子，这种碰撞也可能是由电荷交换引起的。总碰撞频率不是极化和电荷交换分量的总和，但基本上等于主导分量。只有在典型的转变温度附近，即电离层温度范围（通常为200-2000 K）附近，总辐射量才会增加。然而，这种增强的幅度在以前的研究中有所不同;最大增强被报道为41%和11%，没有物理解释。在本研究中，极化力对电荷交换碰撞的贡献表示为简单的弯曲粒子轨道效应。结果，发现最大增强为22%。讨论了经典电离层研究中忽略的增强效应，部分原因是由于与掠射粒子贡献（增加了10.5%的极化分量）的混淆。这种增强被忽略的原因可能也是因为没有一种功能形式来表达它。
Collision between ions and neutral particles is an essential characteristic of Earth's ionosphere. This ion‐neutral collision is usually caused by the polarization of neutral particles. This collision can also be caused by charge exchange, if the particle pair is parental, such as atomic oxygen and its ion. The total collision frequency is not the sum of the polarization and charge‐exchange components, but is essentially equal to the dominant component. The total is enhanced only around the classic transition temperature, which is near the ionospheric temperature range (typically 200–2000 K). However, the magnitude of this enhancement has differed among previous studies; the maximum enhancement has been reported as 41% and 11% without physical explanation. In the present study, the contribution of the polarization force to the charge‐exchange collision is expressed as a simple curved particle trajectory effect. As a result, the maximum enhancement is found to be 22%. It is discussed that the enhancement has been neglected in classic ionospheric studies partly due to confusion with the glancing particle contribution, which adds 10.5% to the polarization component. The enhancement has been neglected presumably also because there has been no functional form to express it. Such an expression is derived in this study.