Abstract. 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 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 3 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) HSS (ICME) occurrence.

中文翻译：

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外辐射带相对论电子的半年变化

摘要。在太阳周期24期间，使用Van Allen探针（MagEIS和REPT）和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2000年进行小波和交叉小波分析电子通量的广泛能量和空间范围，并检查它们与轴向，等角和Russell-McPherron机理的相位关系。发现相对论电子通量的半年变化在高于3.5的L壳层处在0.3–4.2 MeV的能量范围内表现出明显的功率，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，