The Association of High-Latitude Dayside Aurora With NBZ Field-Aligned Currents
The Association of High-Latitude Dayside Aurora With NBZ Field-Aligned Currents
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DOI：
10.1029/2017ja025082
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发表时间：
2018-05-01
影响因子：
2.8
通讯作者：
Anderson, B. J.
中科院分区：
文献类型：
--
作者：
Carter, J. A.;Milan, S. E.;Anderson, B. J.
极地电离层极光发射与地球磁层内大规模电流流动之间的关系尚待全面确定。在北向行星际磁场（IMF）条件下，磁重联发生在高纬度磁层顶，激发了向阳面极地电离层中的两个反向叶对流单体，并允许太阳风等离子体进入，通过直接影响大气形成极光尖点。据推测，NBZ极光的第二类，高纬度昼侧极光，是由向上的场对准电流与叶对流。在这里，我们提出的数据从特殊传感器紫外线光谱成像仪仪器和活动磁层和行星电动力学响应实验，从2010年1月至2013年9月，在一个大型的统计研究。我们揭示了一个向北的国际货币基金组织极光现象，位于附近的尖点，并与一个地区的向上电流顺时针旋转叶细胞。发射只发生在阳光照射的夏季半球，表明电流闭合的电离层电导的影响。此外，快速的太阳风速度需要这种发射是明亮的。结果表明，昼侧极光发射是由IMF-磁层电动力学耦合以及太阳风对大气的直接影响产生的，证实了高纬昼侧极光与NBZ电流的关联。
The relationship between auroral emissions in the polar ionosphere and the large-scale flow of current within the Earth's magnetosphere has yet to be comprehensively established. Under northward interplanetary magnetic field (IMF) conditions, magnetic reconnection occurs at the high-latitude magnetopause, exciting two reverse lobe convection cells in the dayside polar ionosphere and allowing ingress of solar wind plasma to form an auroral cusp spot by direct impact on the atmosphere. It has been hypothesized that a second class of NBZ auroras, High-latitude Dayside Aurora, are produced by upward field-aligned currents associated with lobe convection. Here we present data from the Special Sensor Ultraviolet Spectrographic Imager instrument and from the Active Magnetosphere and Planetary Electrodynamics Response Experiment, from January 2010 to September 2013, in a large statistical study. We reveal a northward IMF auroral phenomenon that is located adjacent to the cusp spot and that is colocated with a region of upward electrical current in the clockwise-rotating lobe cell. The emission only occurs in the sunlit summer hemisphere, demonstrating the influence of the conductance of the ionosphere on current closure. In addition, fast solar wind speed is required for this emission to be bright. The results show that dayside auroral emission is produced by IMF-magnetosphere electrodynamic coupling, as well as by direct impact of the atmosphere by the solar wind, confirming the association of High-latitude Dayside Aurora with NBZ currents.