Ionospheric signatures of internal reconnection for northward interplanetary magnetic field: Observation of “reciprocal cells” and magnetosheath ion precipitation
Ionospheric signatures of internal reconnection for northward interplanetary magnetic field: Observation of “reciprocal cells” and magnetosheath ion precipitation
复制标题
向北行星际磁场内部重联的电离层特征：“互逆细胞”和磁鞘离子沉淀的观测
DOI：
10.1029/2005ja011446
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
K. Kabin
中科院分区：
文献类型：
--
作者：
M. Watanabe;G. Sofko;D. André;J. Ruohoniemi;M. Hairston;K. Kabin
[1]由于磁场重联发生在磁层顶内部，因此它涉及到波瓣磁力线的重叠，称为内部重联。当行星际磁场（IMF）是由于北向和地球的偶极子倾斜显着，内部重联发生在冬季半球，不仅在夏季波瓣场线和冬季波瓣场线之间，而且在夏季波瓣场线和闭合场线之间。后者的内部重联驱动"互惠细胞"在冬季电离层，专门循环在封闭的磁力线区域。倒易细胞密切相关的叶细胞在夏季电离层中，在稳定状态下，与合并的IMF和开放场线的重联电压等于叶细胞电位和倒易细胞电位的总和。在本文中，我们提出的对流模式的观测结果与预期的互惠细胞，电离层雷达和低空卫星数据。我们还显示了叶细胞和互惠细胞的共存。倒易细胞的观察提供了支持的内部重联之间的夏季叶场线和一个封闭的场线。此外，我们发现，赤道的极帽边界，磁鞘状离子漂移从中午到flankside在两个半球。我们认为，这些离子的磁鞘起源，他们进入封闭区域的磁层通过旋转不连续性与内部重联。这些磁鞘状离子的观测强烈支持内部重联的发生。
[1] Magnetic reconnection that involves overdraped lobe field lines is called internal reconnection since it occurs inside the magnetopause. When the interplanetary magnetic field (IMF) is due northward and the Earth's dipole is tilted significantly, internal reconnection occurs in the winter hemisphere, not only between a summer lobe field line and a winter lobe field line but also between a summer lobe field line and a closed field line. The latter internal reconnection drives “reciprocal cells” in the winter ionosphere that circulate exclusively in the closed field line region. The reciprocal cells are intimately related to the lobe cells in the summer ionosphere in that in the steady state, the reconnection voltage associated with merging of IMF and open field lines is equal to the sum of the lobe cell potential and the reciprocal cell potential. In this paper we present observations of convection patterns consistent with those expected for reciprocal cells, using ionospheric radar and low-altitude satellite data. We also show the concurrence of lobe cells and reciprocal cells. The observations of reciprocal cells provide support for the internal reconnection between a summer lobe field line and a closed field line. In addition, we show that equatorward of the polar cap boundary, magnetosheath-like ions are drifting from noon toward the flankside in both hemispheres. We suggest that these ions are of magnetosheath origin and that they entered the closed region of the magnetosphere through the rotational discontinuity associated with internal reconnection. These magnetosheath-like ion observations strongly support the occurrence of internal reconnection.