The reason for the wide particle spread during the 17 April 2021 SEP event
- 1Department of Physics and Astronomy, University of Turku, Finland
- 2Universidad de Alcalá, Space Research Group, Alcalá de Henares, Spain
- 3Leibniz-Institut für Astrophysik Potsdam (AIP), Potsdam, Germany
- 4Department of Physics, George Washington University, Washington, DC, USA
- 5Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- 6Skolkovo Institute of Science and Technology, Moscow, Russia
- 7Centre for Space Research, North-West University, Potchefstroom, South Africa
- 8The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
- 9Institute of Experimental and Applied Physics, Kiel University, Kiel, Germany
- 10California Institute of Technology, Pasadena, CA, USA
- 11Predictive Science Inc., San Diego, CA, USA
- 12Faculty of Science, University of Helsinki, Helsinki, Finland
- 13School of Physics and Astronomy, University of Leicester, Leicester, UK
The widespread SEP event of 17 April 2021 was observed by five longitudinally well-separated observers in the inner heliosphere covering distances to the Sun from 0.42 to 1 au: BepiColombo, Parker Solar Probe, Solar Orbiter, STEREO A, and close-to-Earth spacecraft. The event, which produced relativistic electrons and protons, was associated with a complex and long-lasting solar eruption involving a long-duration flare, a medium-fast Coronal Mass Ejection (CME), an EUV wave and a complex solar radio burst activity lasting for 40 minutes including type II bursts, marking the presence of a shock, as well as four distinct groups of type III bursts. Our comprehensive analysis of the multi-spacecraft in-situ and remote-sensing observations suggests different source regions for the electron and proton SEP event with a stronger shock contribution for the proton event and a more likely flare-related source of the electron event. We furthermore determine that the four distinct injection episodes, marked by the radio type III burst groups, cover a longitudinal range of about 110° and were a main ingredient for the wide SEP spread. We consider this a new scenario that must be taken into account as a potential contributor to widespread SEP events.
How to cite: Dresing, N., Rodríguez-García, L., Jebaraj, I., Warmuth, A., Wallace, S., Balmaceda, L., Podladchikova, T., Strauss, D. T., Kouloumvakos, A., Palmroos, C., Krupar, V., Gieseler, J., Xu, Z., Mitchell, G., Cohen, C., de Nolfo, G., Palmerio, E., Carcaboso, F., Kilpua, E., and Sanchez-Cano, B.: The reason for the wide particle spread during the 17 April 2021 SEP event, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11319, https://doi.org/10.5194/egusphere-egu23-11319, 2023.
