Reconnection at the dayside magnetopause: Comparisons of global MHD simulation results with Cluster and Double Star observations
Reconnection at the dayside magnetopause: Comparisons of global MHD simulation results with Cluster and Double Star observations
复制标题
DOI：
10.1029/2007ja012743
复制
发表时间：
2008-07
影响因子：
--
通讯作者：
J. Berchem;A. Marchaudon;M. Dunlop;C. Escoubet;J. Bosqued;H. Rème;I. Dandouras;A. Balogh;E. Lucek;C. Carr;Z. Pu
中科院分区：
文献类型：
--
作者：
J. Berchem;A. Marchaudon;M. Dunlop;C. Escoubet;J. Bosqued;H. Rème;I. Dandouras;A. Balogh;E. Lucek;C. Carr;Z. Pu
[1]本研究利用星团与双星星星TC-1卫星的两次会合，结合全球磁流体动力学（MHD）模拟，对向阳面磁层顶的大尺度磁重联结构进行了研究。这两个事件涉及南行星际磁场与显着的由组件。第一次事件发生在2004年5月8日，当时两个航天器都在探索磁层的黎明侧翼; TC-1正在掠过磁层顶，而Cluster正在探索更高的纬度。从全球MHD模拟的结果表明，在上午部门赤道合并线的形成，并建议合并区的三维几何形状主要是一个径向并列的平面显示X型重联几何形状。第二次是在2004年4月6日。在这次活动中，星团位于高纬度地区，靠近中午-午夜子午线，而TC-1则在低纬度地区探索黎明。模拟分析表明，反平行和组件合并同时发生。平行电场的三维渲染表明，分量合并开始于太阳下磁层顶。在模型中使用不同的参数进行模拟运行表明，合并区域的扩展取决于当地的电阻率。太阳下的合并区域的增长与电阻率值的增加，并成为补丁时，使用的电阻率阈值。然而，该区域的组件合并似乎仍然在空间上限制到太阳下区域，在那里发生更强的平行电场，并没有明确的连接与反平行合并区域被发现的参数范围内调查。
[1] This study uses two conjunctions between Cluster and Double Star TC-1 spacecraft together with global magnetohydrodynamic (MHD) simulations to investigate the large-scale configuration of magnetic reconnection at the dayside magnetopause. Both events involve southward interplanetary magnetic fields with significant By components. The first event occurred on 8 May 2004, while both spacecraft were exploring the dawn flank of the magnetosphere; TC-1 was skimming the magnetopause whereas Cluster was exploring higher latitudes. Results from a global MHD simulation show the formation of an equatorial merging line in the morning sector and suggest that the three-dimensional geometry of the merging region is mostly a radial juxtaposition of planes displaying X-type reconnection geometries. The second conjunction was on 6 April 2004. During this event, Cluster was located at high latitudes and close to the noon-midnight meridian, while TC-1 was exploring the dawnside at low latitudes. Analysis of the simulation reveals that both antiparallel and component merging occurred simultaneously. Three-dimensional rendering of the parallel electric field indicates that component merging initiated in the subsolar magnetopause. Simulation runs carried out using different parameters in the model suggest that the spread of the merging region depends on the local resistivity. The subsolar-merging region grows with increasing resistivity values and becomes patchy when a resistivity threshold is used. However, the region of component merging appears to remain spatially constrained to the subsolar region where stronger parallel electric fields occur and no clear connection with the antiparallel-merging regions is found for the range of parameters surveyed.