Poleward moving auroral arcs observed at the South Pole Station and the interpretation by field line resonances
Poleward moving auroral arcs observed at the South Pole Station and the interpretation by field line resonances
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南极站观测到的向极移动的极光弧及场线共振的解释
DOI：
10.1029/2012ja017899
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发表时间：
2012
影响因子：
--
通讯作者：
Y.-M
中科院分区：
文献类型：
--
作者：
Tanaka;Y.-M
利用全天单色成像仪在2004年7月8日08：00-11：00 MLT期间在南极站（74.3°CGLAT）观测到的极向移动极光弧（PMAAs）特征进行了研究。在此期间，还观察到Pc 5地磁脉动以及准静止极光斑块（QSAP），它们的形式，亮度和位置保持长达数小时。结果表明，PMAAs、Pc 5南北分量脉动和QSAP东西方向漂移振荡具有相似的优势周期，并且相互之间有很好的相关性。振荡电离层等离子体漂移伴随着PMAAs提取的QSAP的水平运动，并发现向极传播的PMAAs。PMAAs和Pc 5脉动在北向分量中相对于QSAP向西漂移速度的相位关系分别接近于反相和同相。为了检验这些现象是否可以通过场线共振（FLR）来解释，我们使用水平二维模型进行了数值模拟，该模型由极光加速区和电离层组成，并具有时间演化电导率。结果表明，除了PMAA与Pc 5脉动和QSAP的相位关系外，FLR模型能很好地解释实际观测数据。
We investigate the characteristics of poleward moving auroral arcs (PMAAs) observed with the all‐sky monochromatic imager at the South Pole Station (74.3°CGLAT) in the interval 08:00–11:00 MLT on July 8, 2004. During this period, Pc 5 geomagnetic pulsations are also observed as well as quasi‐stationary auroral patches (QSAPs), which keep their forms, luminosities, and locations for up to several hours. It is demonstrated that the PMAAs, Pc 5 pulsations in the north‐south component, and oscillations in the drift of the QSAPs in the east‐west direction have similar dominant periods and are well correlated with each other. The oscillatory ionospheric plasma drifts accompanying the PMAAs are extracted from the horizontal motion of the QSAPs and are found to propagate poleward with the PMAAs. The phase relations of the PMAAs and Pc 5 pulsations in the northward component with respect to the westward drift velocity of the QSAPs are close to anti‐phase and in‐phase, respectively. To examine whether these phenomena can be interpreted by field line resonances (FLRs), we perform a numerical simulation using a horizontally two‐dimensional model that consists of the auroral acceleration region and the ionosphere with time‐evolution conductivity. The results indicate that the observed data can be well explained by the FLR model with realistic physical parameters, except for the phase relation of the PMAAs with respect to the Pc 5 pulsations and the QSAPs.