Dual spacecraft observations of lobe magnetic field perturbations before, during and after plasmoid release
Dual spacecraft observations of lobe magnetic field perturbations before, during and after plasmoid release
复制标题
双航天器观测等离子体团释放之前、期间和之后的波瓣磁场扰动
DOI：
10.1029/1999gl003606
复制
发表时间：
1999
影响因子：
5.2
通讯作者：
P. Sutcliffe
中科院分区：
文献类型：
--
作者：
J. Slavin;M. Hesse;C. Owen;S. Taguchi;D. Fairfield;R. Lepping;S. Kokubun;T. Mukai;A. Lui;R. R. Anderson;H. Matsumoto;P. Sutcliffe
本文研究了IMP 8和Geotail于1995年1月29日在一次亚暴期间返回的数据集，该亚暴导致了等离子体团的喷射。这两个航天器（s/c）位于尾部的北叶，都观察到一个移动压缩区（TCR）。我们表明，在这种情况下，双S/C测量可以用来模拟所有三个维度的基本等离子体团，并估计其膨胀率。对于这一事件，等离子体团的尺寸ΔX = 18，ΔY = 30，ΔZ = 10 Re是由IMP 8和Geotail观测确定的。此外，在从IMP 8移动到Geotail所需的1.5分钟内，TCR的振幅增加了1.2倍。使用磁通量守恒模型，这种波瓣压缩的增加意味着下面的等离子体团正在以140公里/秒的速度膨胀。最后，在等离子体团喷射之后，波瓣磁场的重新配置将磁通量管移动到等离子体团后面的尾流中，在那里它们将变得可用于馈送重连区域。
This study examines a data set returned by IMP 8 and Geotail on January 29, 1995 during a substorm which resulted in the ejection of a plasmoid. The two spacecraft (s/c) were situated in the north lobe of the tail and both observed a traveling compression region (TCR). We show that in this instance dual s/c measurements can be used to model all three dimensions of the underlying plasmoid and to estimate its rate of expansion. For this event plasmoid dimensions of ΔX ∼18, ΔY ∼30, and ΔZ ∼10 Re are determined from the IMP 8 and Geotail observations. Furthermore, a factor of ∼2 increase in the amplitude of the TCR occurred in the 1.5 min it took to move from IMP 8 to Geotail. Modeled using conservation of magnetic flux, this increase in lobe compression implies that the underlying plasmoid was expanding at a rate of ∼140 km/s. Finally, a reconfiguration of the lobe magnetic field followed plasmoid ejection which moved magnetic flux tubes into the wake behind the plasmoid where they would become available to feed the reconnection region.