Theoretical study: Influence of different energy sources on the cusp neutral density enhancement
Theoretical study: Influence of different energy sources on the cusp neutral density enhancement
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理论研究：不同能源对尖点中性密度增强的影响
DOI：
10.1002/jgra.50197
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
R. Lopez
中科院分区：
文献类型：
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作者：
Yue Deng;T. Fuller‐Rowell;A. Ridley;D. Knipp;R. Lopez
利用全球电离层-热层模式（GITM）进行的模拟表明，坡印亭通量和软电子沉淀对于产生近400 km高度的尖峰中性密度增强很重要，这是由挑战小卫星有效载荷（CHAMP）卫星观测到的。在模型的尖端施加75 mW/m2的坡印廷通量可使中性密度增加34%。从100 eV， 2 mW/m2的软电子沉淀中直接加热，在400 km处仅产生5%的中性密度增强。然而，电子沉淀导致的F区电离增强通过增加焦耳加热导致中性密度增强24%。因此，软电子的净效应接近29%，Poynting通量和软粒子降水的综合影响导致400 km处中性密度增加50%以上，这与CHAMP在极端情况下的观测结果一致。随着特征能的增加，400 km处电子沉淀对中性密度的影响急剧减小，900 eV电子对中性密度的影响不大。最后，由于焦耳加热高度的降低，2 keV， 0.3 mW/m2的质子沉淀对中性密度的影响可以忽略不计。
Simulations with the Global Ionosphere‐Thermosphere Model (GITM) show that both Poynting flux and soft electron precipitation are important in producing neutral density enhancements near 400 km altitude in the cusp that have been observed by the Challenging Minisatellite Payload (CHAMP) satellite. Imposing a Poynting flux of 75 mW/m2 in the cusp within the model increases the neutral density by 34%. The direct heating from 100 eV, 2 mW/m2 soft electron precipitation produces only a 5% neutral density enhancement at 400 km. However, the associated enhanced ionization in the F‐region from the electron precipitation leads to a neutral density enhancement of 24% through increased Joule heating. Thus, the net effect of the soft electron is close to 29%, and the combined influence of Poynting flux and soft particle precipitation causes a more than 50% increase in neutral density at 400 km, which is consistent with CHAMP observations in extreme cases. The effect of electron precipitation on the neutral density at 400 km decreases sharply with increasing characteristic energy such that 900 eV electrons have little effect on neutral density. Finally, the impact of 2 keV, 0.3 mW/m2 proton precipitation on the neutral density is negligible due to a lowering of the altitude of Joule heating.
影响因子：
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作者：
G. W. Prölss
通讯作者：
G. W. Prölss