The electron thermal structure in the dayside Martian ionosphere implied by the MGS radio occultation data
The electron thermal structure in the dayside Martian ionosphere implied by the MGS radio occultation data
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MGS 无线电掩星数据暗示的火星日侧电离层中的电子热结构
DOI：
10.1002/2014je004726
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发表时间：
2015
影响因子：
4.8
通讯作者：
Zou H.
中科院分区：
文献类型：
--
作者：
Cui J.;Gal;M.;Zhang S. J.;Vigren E.;Zou H.
我们提出了一个修正的查普曼模型的电离层的火星，允许电子温度的垂直变化。太阳EUV加热和CO2碰撞冷却之间的近似能量平衡适用于火星电离层的昼侧，类似于Withers等人最近提出的方法。该模型的实质是分离中性结构和电子热结构对电离层主层视宽度的贡献。应用该模型的电子密度分布从火星全球勘测者（MGS）无线电掩星测量揭示了一个明显的趋势，升高的电子温度与太阳天顶角（SZA）。电子温度随高度变化的特征长度尺度随SZA的增大而减小。这些观测结果可能意味着终结者附近的顶部热量流入增强，可能是太阳风与火星上层大气相互作用的结果。我们的分析还揭示了一个试探性的不对称电子温度之间的北方和南半球，符合的情况下，电子温度升高的最小磁层。
We propose a revised Chapman model for the ionosphere of Mars by allowing for vertical variation of electron temperature. An approximate energy balance between solar EUV heating and CO2 collisional cooling is applied in the dayside Martian ionosphere, analogous to the method recently proposed by Withers et al. (2014). The essence of the model is to separate the contributions of the neutral and electron thermal structures to the apparent width of the main ionospheric layer. Application of the model to the electron density profiles from the Mars Global Surveyor (MGS) radio occultation measurements reveals a clear trend of elevated electron temperature with increasing solar zenith angle (SZA). It also reveals that the characteristic length scale for the change of electron temperature with altitude decreases with increasing SZA. These observations may imply enhanced topside heat influx near the terminator, presumably an outcome of the solar wind interactions with the Martian upper atmosphere. Our analysis also reveals a tentative asymmetry in electron temperature between the northern and southern hemispheres, consistent with the scenario of elevated electron temperature within minimagnetospheres.