Approximate forms of daytime ionospheric conductance
Approximate forms of daytime ionospheric conductance
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白天电离层电导的近似形式
DOI：
10.1002/2014ja020665
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发表时间：
2014
影响因子：
--
通讯作者：
and N. Nishitani
中科院分区：
文献类型：
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作者：
Ieda;A.;S. Oyama;H. Vanhamäki;R. Fujii;A. Nakamizo;O. Amm;T. Hori;M. Takeda;G. Ueno;A. Yoshikawa;R. J. Redmon;W. F. Denig;Y. Kamide;and N. Nishitani
研究了太阳天顶角（SZA）对电导的依赖性，并利用峰值等离子体产生高度开发了霍尔-彼得森电导比的简单理论形式。使用2012年3月30日在特罗姆斯特罗（67 MLAT）进行的欧洲非相干散射（EISCAT）雷达观测来计算电导。白天的电导与太阳极紫外辐射入射到地球中性大气层产生的等离子体有关。然而，它一直是不确定的，是否以前的电导模型是与理想的查普曼理论等离子体生产一致。我们发现，SZA依赖的电导是一致的查普曼理论经过简单的修改。Pedersen电导可以通过近似等离子体密度高度分布在顶侧E区是平坦的并考虑大气温度的向上梯度来理解。霍尔电导的额外考虑是必要的，其随着SZA的增加而比佩德森电导更快地减小。这种快速下降可能是由于霍尔导电层从中午到夜间变薄造成的。我们用查普曼理论中的峰值产生高度来表示这种变薄。
The solar zenith angle (SZA) dependence of the conductance is studied and a simple theoretical form for the Hall‐to‐Pedersen conductance ratio is developed, using the peak plasma production height. The European Incoherent Scatter (EISCAT) radar observations at Tromsø (67 MLAT) on 30 March 2012 were used to calculate the conductance. The daytime electric conductance is associated with plasma created by solar extreme ultraviolet radiation incident on the neutral atmosphere of the Earth. However, it has been uncertain whether previous conductance models are consistent with the ideal Chapman theory for such plasma productions. We found that the SZA dependence of the conductance is consistent with the Chapman theory after simple modifications. The Pedersen conductance can be understood by approximating the plasma density height profile as being flat in the topsideEregion and by taking into account the upward gradient of atmospheric temperature. An additional consideration is necessary for the Hall conductance, which decreases with increasing SZA more rapidly than the Pedersen conductance. This rapid decrease is presumably caused by a thinning of the Hall conductivity layer from noon toward nighttime. We expressed this thinning in terms of the peak production height in the Chapman theory.