Response of the magnetospheric convection to sudden interplanetary magnetic field changes as deduced from the evolution of partial ring currents
Response of the magnetospheric convection to sudden interplanetary magnetic field changes as deduced from the evolution of partial ring currents
复制标题
从部分环流演化推导出磁层对流对行星际磁场突变的响应
DOI：
10.1029/2001ja009228
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发表时间：
2002
影响因子：
--
通讯作者：
Y. Ebihara
中科院分区：
文献类型：
--
作者：
K. Hashimoto;T. Kikuchi;Y. Ebihara
[1]我们研究了部分环电流（PRC）的行星际磁场（IMF）Bz的突然变化的两个PRC事件的响应，以调查的对流在近地磁尾IMF变化的响应。我们发现，由于中华人民共和国的地面磁场变化开始同时发展在所有当地时间的时间滞后5-11分钟的增长电离层对流检测到的极冠磁强计。地面磁力仪进一步表明，当对流电场开始衰减时，由于IMF向北转向，不对称环电流变为对称环电流，没有明显的时滞（<1分钟）。等离子体压力和地面磁扰动的时间和空间演化，由于PRC的模拟所涉及的事件使用粒子模拟模型。模拟结果在时间变化和当地时间依赖性方面与观测结果吻合得很好。观测到的PRC的快速发展和重新配置表明，电离层在驱动近地磁尾和内磁层的对流方面发挥了至关重要的作用。特别是，立即重新配置的中华人民共和国所造成的向北转向的国际货币基金组织意味着几乎瞬时传播的电离层对流电场的内磁层和随后的快速变化的环电流配置。本文讨论了对流电场在昼侧磁层中沿着磁场线传播后，通过电离层向近地磁尾的传播。
[1] We examined the response of the partial ring current (PRC) to sudden changes in the interplanetary magnetic field (IMF) Bz for two PRC events, in order to investigate the response of the convection in the near-Earth magnetotail to IMF changes. We found that ground magnetic changes due to the PRC started to develop simultaneously at all local times with a time lag of 5–11 min from the growth of the ionospheric convection as detected by the polar cap magnetometers. The ground magnetometers furthermore showed that the asymmetric ring current changed into a symmetric ring current with no significant time lag (<1 min) when the convection electric field started to decay because of the northward turning of the IMF. The temporal and spatial evolution of the plasma pressure and the ground magnetic perturbations due to the PRC are simulated for the events involved using a particle simulation model. The simulation results agree well with the observations in the temporal variations and their local time dependence. The quick development and reconfiguration of the observed PRC suggest that the ionosphere played a crucial role in driving the convection in the near-Earth magnetotail and in the inner magnetosphere. In particular, the immediate reconfiguration of the PRC caused by the northward turning of the IMF implies nearly instantaneous propagation of the ionospheric convection electric field to the inner magnetosphere and subsequent quick change in the ring current configuration. We discuss the propagation of the convection electric field to the near-Earth magnetotail through the ionosphere after its propagation along the magnetic field lines from the generator in the dayside magnetosphere.