Study on development and decay of inner magnetospheric disturbances by using ground and satellite multipoint observations

地磁风暴期间的磁场变化是由磁层电流（如环电流）和地球内部的感应电流共同产生的。以往的研究报道，感应电流引起的磁场变化约为Dst指数的25%；但我们发现地球感应电流的贡献在20%到55%之间变化，这取决于Dst指数的变化率。关于环电流的发展，我们认为与双极化相关的磁波动对预先存在的冷离子的非绝热加速比等离子体片向内磁层注入高能粒子起更重要的作用。

The field variations during geomagnetic storms are produced by both the magnetospheric currents such as the ring current and the induced currents inside the Earth’s interior. Previous studies have reported that the magnetic field variations due to the induced currents are about 25% of the Dst index; but we found that the Earth-induced current contribution varies between 20% and 55%, and depends on the rate of change of the Dst index. With regard to ring current development, we suggest that the non-adiabatic acceleration of preexisting cold ions by magnetic fluctuations associated with dipolarization plays a more important role than the energetic particle injection from the plasma sheet into the inner magnetosphere.