2000年4月6日磁暴期间磁扰变化在低续子午链的纬度效应

利用低纬地磁午链上H和D分量的分均值数据，分析了2000年4月6日磁暴期间磁扰变化的纬度效应。主要特点是：（1）急始期间H分量急始跃变 幅随磁纬降低而减小，且急始变幅的下降率磁纬降低而逐渐增大；（2）初相期间H分量第2峰值的变幅和初相持续时间随磁纬降低而减小；（3）主相期间H分量迅速减小，并随纬度降低最大变幅明显增加；（4）恢复相H分量呈两阶段上升趋势，前一阶段迅速上升，后一了阶段上升速度明显减小。最后对这些磁扰变化的纬度效应与空间电流体系的密切关系作了讨论。     

Propagation characteristics of the Pc3 frequency range pulsations in the cusp latitudes

Two induction magnetometers have been installed at Zhongshan Station and Davis Station, Antarctica respectively. We adopt with cross-spectral analysis technique to analyze the data of the two induction magnetometers, in June, September,December 1996 and March 1997. to investigate the Pc3 frequency range pulsation occurrence and propagation characteristics in the cusp latitudes. The results are summarized as following:At Zhongshan-Davis Stations, the Pc3 frequency range pulsations occur mainly around the local noon/ local magnetic noon and local magnetic midnight respectively. In daytime, the pulsations have a seasonal variation in amplitude, occurrence and temporal range, all of them are sma1lest in winter. But in nighttime, the pulsations have no such a variation. The pu1sation amplitude in nighttime is much larger than the one in daytime all oveI the year. The pulsation propagating direction is mainly western in daytime and irregularly in nighttime. It can be thought that the different sources of the pulsation and the ionospheric electric conductivity are mainly responsible for these characteristics.