%0 Journal Article %T A preliminary exploration of the mechanism for the occurrence of two types of various magnetic structures in the magnetotail %A Shuping Jin %A Xianpeng Hu %A Hailong Cui %A Zhenxing Liu %A Zuyin Pu %A B. Wilken %J Chinese Science Bulletin %@ 1861-9541 %D 2001 %I %R 10.1007/BF03183540 %X As well known, the magnetic cross-tail component By in the magnetotail is in direct proportion to the interplanetary magnetic field (IMF) B y component. And the polarity of IMF and plasmoid / flux rope B y components do indeed agree. This results indicate that the IMF B y penetrates plasmoids and the magnetic structures must therefore be three-dimensional. In this note, the dynamical processes of magnetotail in the course of a substorm are studied using a MHD code with two-dimensions and three components on the basis of two types of initial equilibrium solutions of the quiet magnetotail. The numerical results of two cases illustrate various features of time evolution of By component that correspond to two kinds of plasmoid-like structures: one is associated with a flux rope core and the other resembles a ˇ°closed loopˇ± plamoid. Therefore, the occurrence of various magnetic structures in the magnetotail might be related to nonsteady driven reconnection with different distributions of the B y component. %K magnetospheric substorm %K magnetic cross-tail component B y %K plasmoid-like structures %K nonsteady magnetic reconnection %U http://link.springer.com/article/10.1007/BF03183540