Nighttime magnetic field fluctuations in the topside ionosphere at midlatitudes and their relation to medium‐scale traveling ionospheric disturbances: The spatial structure and scale sizes
Nighttime magnetic field fluctuations in the topside ionosphere at midlatitudes and their relation to medium‐scale traveling ionospheric disturbances: The spatial structure and scale sizes
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DOI：
10.1002/2015ja021315
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发表时间：
2015-08
期刊：
影响因子：
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通讯作者：
Jaeheung Park;H. Lühr;G. Kervalishvili;J. Rauberg;I. Michaelis;C. Stolle;Y. Kwak
中科院分区：
文献类型：
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作者：
Jaeheung Park;H. Lühr;G. Kervalishvili;J. Rauberg;I. Michaelis;C. Stolle;Y. Kwak
以前的研究表明，在中纬度地区的夜间顶侧电离层中观察到的电场和/或磁场波动通常源于安静时间的夜间中等规模电离层扰动（MSTID）。然而，两者之间的联系的决定性证据一直缺失。在这项研究中，我们利用多航天器观测中纬度磁波动（MMF）在夜间顶侧电离层的Swarm星座。分析结果表明，在北方（南）半球，磁流变场的活动区域呈北西-东南（NE-SW）方向拉长。伸长方向和磁场极化支持托管MMF的区域几乎是场对准的。所有这些性质都表明，它们与MSTID有着密切的关系。与MMF相关的均方根场向电流的期望值高达约4 nA/m2。纵向距离≥1 mm时，MMF相干性显著下降。
Previous studies suggested that electric and/or magnetic field fluctuations observed in the nighttime topside ionosphere at midlatitudes generally originate from quiet time nocturnal medium‐scale traveling ionospheric disturbances (MSTIDs). However, decisive evidences for the connection between the two have been missing. In this study we make use of the multispacecraft observations of midlatitude magnetic fluctuations (MMFs) in the nighttime topside ionosphere by the Swarm constellation. The analysis results show that the area hosting MMFs is elongated in the NW‐SE (NE‐SW) direction in the Northern (Southern) Hemisphere. The elongation direction and the magnetic field polarization support that the area hosting MMFs is nearly field aligned. All these properties of MMFs suggest that they have close relationship with MSTIDs. Expectation values of root‐mean‐square field‐aligned currents associated with MMFs are up to about 4 nA/m2. MMF coherency significantly drops for longitudinal distances of ≥1∘.