EGU21-13458
https://doi.org/10.5194/egusphere-egu21-13458
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

On the semi-annual variation of relativistic electrons in the outer radiation belt

Sigiava Aminalragia-Giamini1,2, Christos Katsavrias1,2, Constantinos Papadimitriou1,2, Ioannis A. Daglis1,3, Ingmar Sandberg2, and Piers Jiggens4
Sigiava Aminalragia-Giamini et al.
  • 1National and Kapodistrian University of Athens, Department of Physics, Greece
  • 2Space Applications and Research Consultancy (SPARC), Athens, Greece
  • 3Hellenic Space Center, Athens, Greece
  • 4ESA/ESTEC, Netherlands

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.

This work has received funding from the European Union's Horizon 2020 research and innovation programme “SafeSpace” under grant agreement No 870437 and from the European Space Agency under the “European Contribution to International Radiation Environment Near Earth (IRENE) Modelling System” activity under ESA Contract No 4000127282/19/NL/IB/gg.

How to cite: Aminalragia-Giamini, S., Katsavrias, C., Papadimitriou, C., A. Daglis, I., Sandberg, I., and Jiggens, P.: On the semi-annual variation of relativistic electrons in the outer radiation belt, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13458, https://doi.org/10.5194/egusphere-egu21-13458, 2021.

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