Geomagnetic conjugate observations of medium‐scale traveling ionospheric disturbances at midlatitude using all‐sky airglow imagers
Geomagnetic conjugate observations of medium‐scale traveling ionospheric disturbances at midlatitude using all‐sky airglow imagers
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DOI：
10.1029/2004gl020262
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发表时间：
2004-08
影响因子：
5.2
通讯作者：
Yuichi Otsuka;K. Shiokawa;T. Ogawa;P. Wilkinson
中科院分区：
文献类型：
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作者：
Yuichi Otsuka;K. Shiokawa;T. Ogawa;P. Wilkinson
我们首次报道了在中纬度地区使用两台全天气辉成像仪在两个半球的地磁共轭点处同时观测到中等尺度的行进电离层扰动(MSTID)。2002年8月9日晚上，日本SATA的一台630 nm全天CCD成像仪探测到了波前从西北向东南延伸的MSTID。在这次事件中，在澳大利亚达尔文的地磁共轭点观测到了波前从西南向东北方向拉长的MSTID。为了研究MSTID结构的地磁共轭关系，绘制了达尔文图像，沿地磁线(B)绘制的MSTID结构与SATA图像中的MSTID结构非常吻合。这一结果表明，极化电场在MSTID的产生中起着重要的作用。EP沿B方向作图，使F区等离子体以E×B漂移的方式向上或向下移动，导致等离子体密度扰动，结构镜像在南北半球。
We report for the first time simultaneous observations of medium‐scale traveling ionospheric disturbances (MSTIDs) at geomagnetic conjugate points in both hemispheres, using two all‐sky airglow imagers at midlatitudes. A 630‐nm all‐sky CCD imager at Sata, Japan, detected MSTIDs with a wavefront elongated from NW to SE on the night of August 9, 2002. During this event, MSTIDs with a wavefront elongated from SW to NE were observed at the geomagnetic conjugate point, Darwin, Australia. To investigate geomagnetic conjugacy of the MSTID structures, the Darwin images were mapped The MSTID structures mapped from Darwin to its magnetic conjugate points along the geomagnetic field lines (B) coincide closely with those in the Sata images. This result suggests that polarization electric field (Ep) plays an important role in the generation of MSTIDs. Ep maps along B and moves the F region plasma upward or downward by E × B drifts, causing plasma density perturbations with structures mirrored in the northern and southern hemispheres.