EGU21-11753, updated on 14 Jan 2022
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Coordinated observations of relativistic electron enhancements following an HSS period 

Afroditi Nasi1, Ioannis A. Daglis1,2, Christos Katsavrias1, Ingmar Sandberg3, Wen Li4, Yoshizumi Miyoshi5, Shun Imajo5, Takefumi Mitani6, Tomo Hori5, Satoshi Kasahara7, Shoichiro Yokota8, Kunihiro Keika7, Iku Shinohara6, Ayako Matsuoka9, and Yoshiya Kasahara10
Afroditi Nasi et al.
  • 1Department of Physics, National and Kapodistrian University of Athens, Athens, Greece (
  • 2Hellenic Space Center, Athens, Greece
  • 3Space Applications & Research Consultancy (SPARC), Greece
  • 4Center for Space Physics, Boston University, Boston, MA, USA
  • 5Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
  • 6Japan Aerospace Exploration Agency, Japan
  • 7University of Tokyo, Tokyo, Japan
  • 8Osaka University, Osaka, Japan
  • 9Kyoto University, Kyoto, Japan
  • 10Kazanawa University, Kazanawa, Japan

During the second half of 2019, a sequence of solar wind high-speed streams (VSW ≥ 600 km/s)  impacted the magnetosphere, resulting in a series of recurrent, relatively weak, geomagnetic storms (Dstmin ≥ - 80 nT). During one of these storms, a longer-lasting solar wind pressure pulse and intense substorm activity were also recorded (AL ≤ - 1600 nT on August 31 and September 1).

We use particle measurements from the Van Allen Probes, Arase and Galileo 207, 215 satellites, to investigate this event; all spacecraft observed a significant enhancement of relativistic electron fluxes. We also use ULF and chorus wave measurements, as well as interplanetary parameters, for a detailed investigation of this event and of the acceleration mechanisms involved.

This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870437 for the SafeSpace project.

How to cite: Nasi, A., Daglis, I. A., Katsavrias, C., Sandberg, I., Li, W., Miyoshi, Y., Imajo, S., Mitani, T., Hori, T., Kasahara, S., Yokota, S., Keika, K., Shinohara, I., Matsuoka, A., and Kasahara, Y.: Coordinated observations of relativistic electron enhancements following an HSS period , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11753,, 2021.


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