Solar wind control of the radial distance of the magnetic reconnection site in the magnetotail
Solar wind control of the radial distance of the magnetic reconnection site in the magnetotail
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DOI：
10.1029/2005ja011207
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发表时间：
2005-09
影响因子：
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通讯作者：
T. Nagai;M. Fujimoto;R. Nakamura;Wolfgang Baumjohann;A. Ieda;I. Shinohara;S. Machida;Y. Saito;T. Mukai
中科院分区：
文献类型：
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作者：
T. Nagai;M. Fujimoto;R. Nakamura;Wolfgang Baumjohann;A. Ieda;I. Shinohara;S. Machida;Y. Saito;T. Mukai
[1] 为了了解磁尾动力学，必须确定亚暴期间近地磁尾中磁重联发生的位置。 1995 年至 2003 年期间，Geotail 航天器在 10-31 RE 的径向距离处彻底调查了近地等离子体层。使用强电子加速标准识别了 34 个清晰的重连接事件。检查每次重联事件之前的各种太阳风参数，以便找到控制磁尾中磁重联位点位置的因素。对快速尾流事件进行了相同的分析。最重要的因素被确定为太阳风能量输入，可以用−Vx × Bs 表示，其中Vx 是太阳风速度的x 分量，Bs 是行星际磁场的南向分量。可能是较高的能量输入效率而不是能量输入总量主要控制磁重联的位置；当能量输入效率较高时，磁重联发生在离地球较近的地方。太阳风动压的影响较小。目前的结果表明，亚暴期间尾部磁重联位置受太阳风中太阳周期变化的控制。
[1] To understand magnetotail dynamics, it is essential to determine where magnetic reconnection takes place in the near-Earth magnetotail during substorms. The Geotail spacecraft thoroughly surveyed the near-Earth plasma sheet at radial distances of 10–31 RE during the years 1995–2003. Thirty-four clear reconnection events were identified using the criterion of strong electron acceleration. Various solar wind parameters prior to each reconnection event were examined in order to find the factor controlling the location of the magnetic reconnection site in the magnetotail. The same analyses were carried out for fast tailward flow events. The most important factor was determined to be the solar wind energy input, which can be expressed by −Vx × Bs, where Vx is the x component of the solar wind velocity and Bs is the southward component of the interplanetary magnetic field. It is likely that higher efficiency of energy input, rather than the total amount of energy input, primarily controls the location of magnetic reconnection; magnetic reconnection takes place closer to the Earth when efficiency of energy input is higher. The effect of solar wind dynamic pressure is minor. The present result suggests that the tail magnetic reconnection location during substorms is controlled by solar cycle variations in the solar wind.