Evidence for day‐to‐night ion transport at low solar activity in the Venus pre‐dawn ionosphere
Evidence for day‐to‐night ion transport at low solar activity in the Venus pre‐dawn ionosphere
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金星黎明前电离层太阳活动低时昼夜离子传输的证据
DOI：
10.1029/93gl02422
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发表时间：
1993
影响因子：
5.2
通讯作者：
H. Porter
中科院分区：
文献类型：
--
作者：
J. Brannon;J. Fox;H. Porter
先锋金星航天器于 1992 年 8 月 28 日午夜时分降至 180 公里以下，在 1992 年 10 月航天器失去联系之前，获得了黎明前区域中度低太阳活动的 42 个低空轨道数据。通过对 PV 轨道飞行器离子质谱仪 (OIMS) 数据的分析和建模的结合，我们在此考虑可以从日面了解到等离子体传输的相对重要性。再入期间维持夜间电离层的电子沉淀。特别是，我们在这里检查原子离子密度分布。我们计算 O+ 的平均峰值密度作为太阳天顶角的函数，并确定产生这些值所需的原子离子或沉淀电子通量。然后，我们将离子密度的模型计算与再入期间观察到的离子密度进行比较。我们发现低太阳活动的夜间电离层显示出明显的昼夜等离子体传输的证据。
Periapsis of the Pioneer Venus spacecraft dropped below 180 km on August 28, 1992 near midnight, and 42 orbits of low altitude data at moderately low solar activity in the pre-dawn sector were obtained before contact was lost to the spacecraft in October, 1992. Through a combination of analysis of data from the PV orbiter ion mass spectrometer (OIMS) and modeling, we consider here what can be learned about the relative importance of plasma transport from the dayside and electron precipitation in maintaining the nightside ionosphere during the re-entry period. In particular, we examine here the atomic ion density profiles. We compute the average peak density of O+ as a function of solar zenith angle and determine what fluxes of atomic ions or precipitating electrons would be necessary to produce those values. We then compare model calculations of the ion densities to those observed during the re-entry period. We find that the low solar activity nightside ionosphere shows evidence of significant day-to-night plasma transport.