Altitude distribution of the auroral acceleration potential determined from cluster satellite data at different heights.
Altitude distribution of the auroral acceleration potential determined from cluster satellite data at different heights.
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DOI：
10.1103/physrevlett.106.055002
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发表时间：
2011-02
影响因子：
8.6
通讯作者：
G. Marklund;Soheil Sadeghi;T. Karlsson;P. Lindqvist;H. Nilsson;C. Forsyth;A. Fazakerley;E. Lucek-E.-Luce
中科院分区：
文献类型：
--
作者：
G. Marklund;Soheil Sadeghi;T. Karlsson;P. Lindqvist;H. Nilsson;C. Forsyth;A. Fazakerley;E. Lucek-E.-Luce
极光常见于极地天空，是地球和其他太阳系行星上普遍存在的现象。彩色发射是由电子束在 1-2 R(E) 高度的准静态电场或波电场加速后撞击高层大气而引起的。尽管过去的许多卫星任务都对极光进行了研究，但 Cluster 是第一个利用多探测器探索极光加速区域的卫星。在这里，集群数据用于确定极光上方的加速潜力并解决其在空间和时间上的稳定性。导出的电势由两个上部较宽的 U 形电势和下部较窄的 S 形电势组成，并且在 5 分钟时间范围内保持稳定。电场相对于电流的尺度大小强烈依赖于加速区域内的高度。只有结合两颗卫星的数据才能揭示这些特征。
Aurora, commonly seen in the polar sky, is a ubiquitous phenomenon occurring on Earth and other solar system planets. The colorful emissions are caused by electron beams hitting the upper atmosphere, after being accelerated by quasistatic electric fields at 1-2 R(E) altitudes, or by wave electric fields. Although aurora was studied by many past satellite missions, Cluster is the first to explore the auroral acceleration region with multiprobes. Here, Cluster data are used to determine the acceleration potential above the aurora and to address its stability in space and time. The derived potential comprises two upper, broad U-shaped potentials and a narrower S-shaped potential below, and is stable on a 5 min time scale. The scale size of the electric field relative to that of the current is shown to depend strongly on altitude within the acceleration region. To reveal these features was possible only by combining data from the two satellites.