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利用TC1、Cluster和Polar结合极光和同步高度及地磁的观测,研究了2004年9月14日1730～1930UT时间段的亚暴偶极化过程.此前行星际磁场持续南向几个小时.亚暴初发(Onset)开始于1823UT.2min之后,同步高度的LANL-02A在子夜附近观测到了明显的能量电子增强(Injection)事件,而TC1在1827UT左右在磁尾(-10,-2,0)RE(GSE)观测到了磁场BX的突然下降,伴随着等离子体压强和温度的突然增加及磁场的强烈扰动.在(-16,1,3)RE(GSE)的Cluster上相同的仪器观测到相同的现象,只是比TC1观测到的晚大约23min,在1850UT左右.虽然Polar在更靠近地球的较高纬度(-7.5,3.5,-4.0)RE(GSE)附近,也在1855UT左右观测到了这种磁场偶极化现象.以上的观测时序表明TC1、Cluster观测到的磁场偶极化比亚暴偶极化初始发生分别晚4min和27min.说明偶极化由近磁尾向中磁尾传播.详细计算表明偶极化源区的位置大约在X=-7.7RE～-8.6RE,而传播速度大约为70km.s-1.在这个事件中亚暴的物理图像可能是中磁尾的近地重联产生的地向高速流到达近磁尾,为近磁尾的亚暴触发创造了条件;亚暴在近磁尾触发之后,磁场偶极化峰面向中磁尾传播.
Using TC1, Cluster and Polar combined with aurora and synchrotron height and geomagnetic observations, the submarine dipolarization of the period from 1730 to 1930 UT on September 14, 2004 was studied, and the previous interplanetary magnetic field continued to go south for several hours. Atset began at 1823.2 minutes later, and at the same height, LANL-02A observed significant energy electron injection events around midnight, while TC1 was observed at the magnetotail (-10, -2, 0) RE (GSE) A sudden drop in magnetic field BX was observed with a sudden increase in plasma pressure and temperature and a strong perturbation of the magnetic field The same instrument on Cluster of (-16,1,3) RE (GSE) observed the same Only about 23 min later than that observed by TC1 at about 1850 UTC Although this Polar is also observed at around 1855 UT closer to the Earth’s higher latitudes (-7.5, 3.5, -4.0) RE (GSE) Magnetic field dipolarization. The above observation shows that TC1, Cluster observed dipole dipole dipole dipole dipolarization initially occurred later than 4min and 27min later, indicating dipolarization from the near-tail magnetic flux tail. Calculations show that the dipolar source region is about X = -7.7RE ~ -8.6RE, while the propagation velocity About 70km.s-1. The physical image of the sub-storm in this event may be due to the near-surface reassociation of the middle magnet tail to the near-magnetosphere at high velocity, which creates the conditions for the sub-stub trigger near the tail. Sub-storm near the magnetic tail trigger, the magnetic dipole peak for the magnetic tail propagation.