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首页> 外文期刊>Journal of Geophysical Research, A. Space Physics: JGR >Dayside magnetospheric and ionospheric responses to solar wind pressure increase: Multispacecraft and ground observations
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Dayside magnetospheric and ionospheric responses to solar wind pressure increase: Multispacecraft and ground observations

机译：的光面磁层、电离层响应太阳风的压力增加:Multispacecraft和地面观测

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摘要

We provide in situ observations of the transient phenomena in the dayside magnetosphere during the preliminary impulse (PI) and main impulse (MI) event on 30 September 2008. The PI and MI geomagnetic signals are induced by twin traveling convection vortices with opposite polarities in the equivalent ionospheric currents due to a sudden increase of the solar wind dynamic pressure. The two PI-associated ionospheric current vortices centered at ~07 magnetic local time (MLT), 67° magnetic latitude (MLAT) in the dawnside and ~14 MLT, 73°MLAT in the duskside, respectively. The dawnside MI current vortex centered at ~68° MLAT and 6 MLT, while the duskside vortex center was traveling poleward from ~67° MLAT to ~75° MLAT at a speed of ~5.6–7.4 km/s around 14 MLT. It is found that both dawnside PI- and MI-related current vortices were azimuthally seen up to 4 MLT. Following the magnetosphere sudden impulse, a clockwise flow vortex with a radial scale larger than 3 R_E, associated with positive field-aligned current (FAC), was observed by Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft in the outer dayside magnetosphere. The flow vortex expanded and traveled tailward in the magnetosphere, also being reproduced with global MHD simulations. Based on both observation and simulation technique, we show that the MI-related FACs are correlated with the large-scale flow vortex. The PI FACs are partially provided by the mode conversion of fast mode waves into the Alfvén waves near the equatorial plane, while most of it may be generated at a higher-latitude region in the magnetosphere.
机译：我们提供原位观测的瞬态在磁层的光面现象初步脉冲(PI)和主脉冲(MI)2008年9月30日的事件。地磁信号由双旅行对流涡相反的极性由于等效电离层电流突然增加的太阳风动态压力。当前的漩涡中心在当地~ 07磁时间(MLT), 67°磁纬度(MLAT)dawnside ~ 14 MLT, 73°MLAT duskside,分别。集中在~ 68°MLAT和6匝的,虽然duskside向极涡中心旅行从~ 67°MLAT ~ 75°MLAT的速度14 MLT周围-7.4 ~ 5.6公里/秒。dawnsideπ-和MI-related当前的漩涡是4 MLT方位看到的。磁气圈突然冲动,顺时针方向流动比3 R_E涡与径向规模更大,与积极field-aligned电流(FAC),被时间的历史事件和观察宏观尺度相互作用在亚暴(裁判)飞船外的光面的磁场。流漩涡扩大和tailward旅行磁气圈,也被复制全球磁流体动力模拟。和模拟技术,我们表明,MI-related流式细胞仪是相关的大规模的漩涡流动。部分提供的模式转换的太快了模式波附近的阿尔芬波赤道平面,而大多数的可能生成的高纬度地区磁气圈。

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