A Two-Dimensional Model of the Ionosphere of Venus
A Two-Dimensional Model of the Ionosphere of Venus
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DOI：
10.1029/ja088ia07p05595
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发表时间：
1983-07
影响因子：
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通讯作者：
T. Cravens;S. Crawford;A. Nagy;T. Gombosi
中科院分区：
文献类型：
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作者：
T. Cravens;S. Crawford;A. Nagy;T. Gombosi
在先驱者金星轨道器的大部分轨道上，金星上都观测到了大量的黑夜电离层。然而，在太阳风动力压强较大的一些轨道上，夜间电离层似乎几乎消失了，只存在于不规则的低密度等离子体斑块中。我们用金星电离层的二维理论模型解释了这些观测结果，该模型采用了经验水平速度。我们发现，离子从白天到夜间的水平传输能够维持黑夜电离层的程度取决于两个参数：(1)流动速度和(2)终点处的电离层高度。我们还研究了电子沉淀在支持夜间电离层中的作用。我们的模型还提供了间接证据，证明金星上的重氢比增加了。
A substantial nightside ionosphere has been observed on Venus during most orbits of the Pioneer Venus Orbiter. However, on some orbits during which the solar wind dynamic pressure was large, the nightside ionosphere seems to have almost disappeared, existing only as irregular patches of low-density plasma. We interpret these observational results using a two-dimensional theoretical model of the ionosphere of Venus in which empirical horizontal velocities are adopted. We show that the degree to which horizontal transport of ions from day to night can maintain the nightside ionosphere depends on two parameters: (1) the flow velocities and (2) the ionopause height at the terminator. We also investigate the role of electron precipitation in supporting a nightside ionosphere. Our model also provides indirect evidence for an enhanced deuterium to hydrogen ratio on Venus.