The nature of the semi-annual variation in the relativistic electron fluxes in the Earth's outer radiation belt is investigated using Van Allen Probes (MagEIS and REPT) and Geostationary Operational Environmental Satellite Energetic Particle Sensor (GOES/EPS) data during solar cycle 24. We perform wavelet and cross-wavelet analysis in a broad energy and spatial range of electron fluxes and examine their phase relationship with the axial, equinoctial and Russell–McPherron mechanisms. It is found that the semi-annual variation in the relativistic electron fluxes exhibits pronounced power in the 0.3–4.2 MeV energy range at L shells higher than 3.5, and, moreover, it exhibits an in-phase relationship with the Russell–McPherron effect, indicating the former is primarily driven by the latter. Furthermore, the analysis of the past three solar cycles with GOES/EPS indicates that the semi-annual variation at geosynchronous orbit is evident during the descending phases and coincides with periods of a higher (lower) high-speed stream (HSS) (interplanetary coronal mass ejection, ICME) occurrence.

中文翻译：

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外辐射带相对论电子的半年变化

使用Van Allen探针（MagEIS和REPT）和地球静止运行环境卫星高能粒子传感器（GOES / EPS）数据研究了地球外部辐射带中相对论电子通量每半年变化的性质。我们在太阳周期24中进行了研究。我们在宽范围的电子通量能量和空间范围内执行小波和小波分析，并检查它们与轴向，等电和Russell-McPherron机理的相位关系。发现相对论电子通量的半年变化在L的0.3–4.2 MeV能量范围内表现出明显的功率壳比3.5高，而且与Russell-McPherron效应呈同相关系，表明前者主要由后者驱动。此外，使用GOES / EPS对过去三个太阳周期的分析表明，地球同步轨道的半年度变化在下降阶段很明显，并且与高（低）高速流（HSS）（行星际日冕）的周期相吻合。大量弹出，即ICME）。