A statistical study of accelerated flow events at the dayside magnetopause
A statistical study of accelerated flow events at the dayside magnetopause
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DOI：
10.1029/94ja00793
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发表时间：
1994-08
影响因子：
--
通讯作者：
L. Scurry;C. Russell;J. Gosling
中科院分区：
文献类型：
--
作者：
L. Scurry;C. Russell;J. Gosling
利用ISEE 2卫星研究了磁层顶电流层和低纬边界层中的加速等离子体流。磁层顶内磁鞘等离子体的加速流动表明重连正在发生或最近已经发生。已经检查了ISEE 2航天器的180多个进出磁层顶的交叉点，以寻找这种重连的证据。在这些轨道，一个很好的确定，总共有58个统计独立的加速流事件被发现，只有一个事件被选择每个入境或出境磁层顶遍历。在这58个事件中，有42个事件的上游太阳风数据可用。这42个遍历检查有关的上游太阳风和磁鞘参数。加速流的发生取决于上游行星际磁场的方向和磁层顶的局部磁剪切。当行星际磁场在太阳磁层坐标系中有向南分量，且磁层顶局部磁切变较大时，加速流的发生率最大。随着磁鞘β的增加，加速流的发生减少。磁切变很小的事件只有在β较低时才发生。这项研究还提供了合并线的长度和倾斜的统计估计。加速流的位置和方向表明，合并最常发生在日下点附近，沿着沿着一条长度约为6 R{sub E}的线，该线根据行星际磁场的方向倾斜。参考文献33篇，15图。«少
Accelerated plasma flows in the magnetopause current layer and low-latitude boundary layer are examined using the ISEE 2 spacecraft. Accelerated flow of magnetosheath plasma inside the magnetopause is an indication that reconnection is occurring or has recently occurred. Over 180 inbound and outbound magnetopause crossings of the ISEE 2 spacecraft have been examined for such evidence of reconnection. Of those orbits for which a good determination could be made, a total of 58 statistically independent accelerated flow events were found where only one event is chosen per inbound or outbound magnetopause traversal. Upstream solar wind data are available for 42 of these 58 events. These 42 traversals are examined in relation to the upstream solar wind and magnetosheath parameters. The occurrence of accelerated flows is found to be dependent upon the direction of the upstream interplanetary magnetic field and the local magnetic shear across the magnetopause. The occurrence rate of accelerated flows is greatest when the interplanetary magnetic field has a southward component in solar magnetospheric coordinates and the local magnetic shear across the magnetopause is large. As the magnetosheath beta increases, the occurrence of accelerated flows decreases. Events in which the magnetic shear is small occur only when themore » beta is low. This study also provides a statistical estimate of the length and tilt of the merging line. The location and direction of the accelerated flows indicate that merging occurs most often near the subsolar point along a line of length {approximately} 6 R{sub E} that tilts in response to the direction of the interplanetary magnetic field. 33 refs., 15 figs.« less