地球同步轨道高能电子变化

结合小波分析及交叉小波分析方法，研究了地球同步轨道高能电子动态变化的多时间尺度结构，分析了电子通量在不同周期随着太阳风速、地磁指数D_st变化的具体特点.结果发现：（1）电子通量的长期变化受控于太阳风速，在太阳活动低值年，电子通量值高，具有明显的13.4天，27.4天及187天周期；交叉小波分析表明，电子通量的13.4天及27.4天周期受太阳风速周期变化信号的影响，187天周期变化受D_st指数周期变化信号的影响.（2）电子通量半年变化主要归因于太阳风的驱动作用，在每年的第100天及270左右达到两次峰值，峰值大小不对称，与D_st指数的谷值大小呈反比.（3）由于冕洞形成过程中的太阳风高速流影响，电子通量具有13.4及27.4天的周期,峰值水平受控于太阳风速结构.

Variations of high energy electrons in the geostationary orbit

The wavelet analysis and the cross wavelet analysis are used to analyze the multi-time scale structure of geostationary high-energy electron variations, and the characteristics of the dynamic electron environment varying with the solar wind and the D_st index were presented. The results are as follows: (1) Long-term variations of electron flux are mainly controlled by the solar wind velocity. The electron flux enhances during the declining phase of the solar cycle with high solar wind velocity, and varies with 13.4-day, 27.4-day and 187-day periodicities. The cross wavelet analysis shows that the 13.4-day and the 27.4-day periodicities are related to the periodicity signal of solar wind velocity, and the 187-day periodicities are related to the periodicity signal of the D_st index. (2) The 187-day periodicity of the geostationary electron flux is mainly due to the solar wind driver, and the electron flux reaches its peaks on about the 100th and 270th day of one year. The two peak values are not equivalent, while they are related to minimums of the D_st index. (3) Due to high speed solar wind streams which originate from trans-equatorial coronal holes, the electron flux varies with 13.4-day, and 27.4-day periodicities. The 27.4-day periodic variations are characterized by three phases: rapid increase, a more steady peak period and rapid decrease, and the electron flux peak level depends on solar wind velocity structure.