Asymmetric multiple auroral arcs and inertial Alfvén waves
Asymmetric multiple auroral arcs and inertial Alfvén waves
复制标题
不对称的多重极光弧和惯性波
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
J. Samson
中科院分区：
文献类型：
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作者：
T. Trondsen;L. Cogger;J. Samson
卡尔加里大学便携式极光成像仪的高分辨率光学观测显示，在极光亚暴期间经常出现不对称的多个小尺度极光弧结构。尽管经典的多弧阵列倾向于呈现出相当对称的配置，其中各个离散弧内的平行运动在横跨弧阵列的中心的方向上相反，但是本文要讨论的多弧通过存在严格朝向通常将限定弧阵列的中心的两个明亮逆流弧的赤道的离散弧来区分。在大多数情况下，这些平行的赤道弧的强度在赤道方向上迅速下降。通过考虑结构的拓扑结构和弧之间的间距，发现观测结果与最近的理论相一致，这些理论认为惯性阿尔文波可能是细尺度极光弧的原因。
High‐resolution optical observations by the University of Calgary Portable Auroral Imager show a frequent occurrence of asymmetric multiple small‐scale auroral arc structures during auroral substorms. Whereas the classical multiple arc array tends to exhibit a fairly symmetrical configuration, with parallel motions within individual discrete arcs being opposite in direction across the center of the arc array, the multiple arcs to be discussed herein are distinguished by the presence of discrete arcs strictly equatorward of the two bright counter‐streaming arcs that would ordinarily define the center of the arc array. The intensity of these parallel equatorward‐lying arcs were in most cases found to decrease rapidly in the equatorward direction. By considering the topology of the structures and the spacing between arcs, observations are found to be consistent with recent theories suggesting inertial Alfvén waves as a possible cause of fine‐scale auroral arcs.