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The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29

Kollhoff, A. and Kouloumvakos, A. and Lario, D. and Dresing, N. and Gómez-Herrero, R. and Rodríguez-García, L. and Malandraki, O. E. and Richardson, I. G. and Posner, A. and Klein, K.-L. and Pacheco, D. and Klassen, A. and Heber, B. and Cohen, C. M. S. and Laitinen, T. and Cernuda, I. and Dalla, S. and Espinosa Lara, F. and Vainio, R. and Köberle, M. and Kühl, R. and Xu, Z. G. and Berger, L. and Eldrum, S. and Brüdern, M. and Laurenza, M. and Kilpua, E. J. and Aran, A. and Rouillard, A. P. and Bučik, R. and Wijsen, N. and Pomoell, J. and Wimmer-Schweingruber, R. F. and Martin, C. and Böttcher, S. I. and Freiherr von Forstner, J. L. and Terasa, J.-C. and Boden, S. and Kulkarni, S. R. and Ravanbakhsh, A. and Yedla, M. and Janitzek, N. and Rodríguez-Pacheco, J. and Prieto Mateo, M. and Sánchez Prieto, S. and Parra Espada, P. and Rodríguez Polo, O. and Martínez Hellín, A. and Carcaboso, F. and Mason, G. M. and Ho, G. C. and Allen, R. C. and Andrews, G. Bruce and Schlemm, C. E. and Seifert, H. and Tyagi, K. and Lees, W. J. and Hayes, J. and Bale, S. D. and Krupar, V. and Horbury, T. S. and Angelini, V. and Evans, V. and O’Brien, H. and Maksimovic, M. and Khotyaintsev, Yu. V. and Vecchio, A. and Steinvall, K. and Asvestari, E. (2021) The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29. Astronomy and Astrophysics, 656 . Art. No. A20. ISSN 0004-6361. doi:10.1051/0004-6361/202140937.

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Context. On 2020 November 29, the first widespread solar energetic particle (SEP) event of solar cycle 25 was observed at four widely separated locations in the inner (≲1 AU) heliosphere. Relativistic electrons as well as protons with energies > 50 MeV were observed by Solar Orbiter (SolO), Parker Solar Probe, the Solar Terrestrial Relations Observatory (STEREO)-A and multiple near-Earth spacecraft. The SEP event was associated with an M4.4 class X-ray flare and accompanied by a coronal mass ejection and an extreme ultraviolet (EUV) wave as well as a type II radio burst and multiple type III radio bursts. Aims. We present multi-spacecraft particle observations and place them in context with source observations from remote sensing instruments and discuss how such observations may further our understanding of particle acceleration and transport in this widespread event. Methods. Velocity dispersion analysis (VDA) and time shift analysis (TSA) were used to infer the particle release times at the Sun. Solar wind plasma and magnetic field measurements were examined to identify structures that influence the properties of the energetic particles such as their intensity. Pitch angle distributions and first-order anisotropies were analyzed in order to characterize the particle propagation in the interplanetary medium. Results. We find that during the 2020 November 29 SEP event, particles spread over more than 230° in longitude close to 1 AU. The particle onset delays observed at the different spacecraft are larger as the flare–footpoint angle increases and are consistent with those from previous STEREO observations. Comparing the timing when the EUV wave intersects the estimated magnetic footpoints of each spacecraft with particle release times from TSA and VDA, we conclude that a simple scenario where the particle release is only determined by the EUV wave propagation is unlikely for this event. Observations of anisotropic particle distributions at SolO, Wind, and STEREO-A do not rule out that particles are injected over a wide longitudinal range close to the Sun. However, the low values of the first-order anisotropy observed by near-Earth spacecraft suggest that diffusive propagation processes are likely involved.

Item Type:Article
Related URLs:
URLURL TypeDescription
Kollhoff, A.0000-0002-9471-5132
Lario, D.0000-0002-3176-8704
Malandraki, O. E.0000-0002-4751-6835
Richardson, I. G.0000-0002-3855-3634
Posner, A.0000-0003-1572-8734
Heber, B.0000-0003-0960-5658
Cohen, C. M. S.0000-0002-0978-8127
Bučik, R.0000-0001-7381-6949
Mason, G. M.0000-0003-2169-9618
Ho, G. C.0000-0003-1093-2066
Allen, R. C.0000-0003-2079-5683
Bale, S. D.0000-0002-1989-3596
Vecchio, A.0000-0002-6254-1617
Additional Information:© A. Kollhoff et al. 2021. Licence Creative CommonsOpen Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Solar Orbiter First Results (Cruise Phase). Received: 30 March 2021 Accepted: 24 May 2021. Solar Orbiter is a space mission of international collaboration between ESA and NASA, operated by ESA. The CAU Kiel team acknowledges support from the German Federal Ministry for Economic Affairs and Energy, the German Space Agency (Deutsches Zentrum für Luft- und Raumfahrt e.V., DLR) under grants 50OT0901, 50OT1202, 50OT1702, and 50OT2002. A.K. acknowledges financial support from the ANR COROSHOCK project (ANR-17-CE31-0006-01). D.L. acknowledges support from NASA-HGI grant NNX16AF73G and the NASA Program NNH17ZDA001N-LWS. This study has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 101004159 (SERPENTINE). The U. Turku team acknowledges funding by the Academy of Finland (Grant No. 336809). The UAH team acknowledges financial support by the Spanish Ministerio de Ciencia, Innovación y Universidades FEDER/MCIU/AEI Projects ESP2017-88436-R and PID2019-104863RB-I00/AEI/10.13039/501100011033. L.R.G. is also supported by the European Space Agency, under the ESA/NPI program, and acknowledges the work performed by Laura Balmaceda and Hebe Cremades in the 3D reconstruction of the CMEs used in the ENLIL simulation. ENLIL simulation results have been provided by the Community Coordinated Modeling Center at NASA Goddard Space Flight Center (GSFC) through their public Runs on Request system (; run IDs Laura_Rodriguez-Garcia_031321_SH_1). The WSA model was developed by C. N. Arge, currently at GSFC, and the ENLIL Model was developed by D. Odstrcil, currently at George Mason University. We thank the STEREO: SECCHI, S/WAVES; SOHO: LASCO; Wind/WAVES; and SDO/AIA teams for providing the data used in this study. The STEREO SECCHI data are produced by a consortium of RAL (UK), NRL (USA), LMSAL (USA), GSFC (USA), MPS (Germany), CSL (Belgium), IOTA (France), and IAS (France). SOHO is a mission of international cooperation between ESA and NASA. The SDO/AIA data are provided by the Joint Science Operations Center (JSOC) Science Data Processing (SDP). We thank the radio monitoring service at LESIA (Observatoire de Paris) for providing value-added data that have been used for this study. The ORFEES radio-spectrograph (Observations Radio pour FEDOME et l’Etude des Eruptions Solaires) is the result of a partnership between Paris Observatory and the French Air Force. CALLISTO is a radio spectrograph network organized by the Institute of Astronomy, ETH Zurich and FHNW Windisch, Switzerland. We acknowledge data from the instruments in Glasgow (UK), Heiterswil (Switzerland), and Trieste (Italy). The RPW instrument has been designed and funded by CNES, CNRS, the Paris Observatory, The Swedish National Space Agency, ESA-PRODEX and all the participating institutes. I.G.R. acknowledges support from NASA programs NNH19ZDA001N-HSR and NNH19ZDA001N-LWS, and the STEREO mission. IRFU team acknowledges support from the Swedish National Space Agency grant 20/136. A.A. acknowledges the support of the Spanish Ministerio de Ciencia e Innovación (MICINN) under grant PID2019- 105510GB-C31 and through the ‘Center of Excellence María de Maeztu 2020-2023’ award to the ICCUB (CEX2019-000918- M). F.C. acknowledges the financial support by the Spanish MINECO-FPI-2016 predoctoral grant with FSE. E.A. would like to acknowledge the financial support by the Academy of Finland (Postdoctoral Grant No 322455). V.K. acknowledges the support by NASA under grants 18-2HSWO218_2-0010 and 19-HSR-19_2-0143. Solar Orbiter magnetometer operations are funded by the UK Space Agency (grant ST/T001062/1). T.S.H. is supported by STFC grant ST/S000364/1. T.L. and S.D. acknowledge support from the UK Science and Technology Facilities Council (STFC; grant ST/R000425/1).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
European Space Agency (ESA)UNSPECIFIED
Bundesministerium für Wirtschaft und Energie (BMWi)UNSPECIFIED
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50OT0901
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50OT1202
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50OT1702
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50OT2002
Agence Nationale pour la Recherche (ANR)ANR-17-CE31-0006-01
European Research Council (ERC)101004159
Academy of Finland336809
Fondo Europeo de Desarrollo Regional (FEDER)UNSPECIFIED
Ministerio de Ciencia, Innovación y Universidades (MICIU)ESP2017-88436-R
Ministerio de Ciencia, Innovación y Universidades (MICIU)PID2019-104863RB-I00/AEI/10.13039/501100011033
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Paris ObservatoryUNSPECIFIED
Swedish National Space Agency20/136
Ministerio de Ciencia e Innovación (MCINN)PID2019-105510GB-C31
Centro de Excelencia Severo OchoaCEX2019-000918-M
Ministerio de Economía, Industria y Competitividad (MINECO)UNSPECIFIED
Academy of Finland322455
United Kingdom Space Agency (UKSA)ST/T001062/1
Science and Technology Facilities Council (STFC)ST/S000364/1
Science and Technology Facilities Council (STFC)ST/R000425/1
Subject Keywords:Sun: particle emission / Sun: heliosphere / Sun: coronal mass ejections (CMEs) / Sun: flares / interplanetary medium
Record Number:CaltechAUTHORS:20211214-82752000
Persistent URL:
Official Citation:The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29 A. Kollhoff, A. Kouloumvakos, D. Lario, N. Dresing, R. Gómez-Herrero, L. Rodríguez-García, O. E. Malandraki, I. G. Richardson, A. Posner, K.-L. Klein, D. Pacheco, A. Klassen, B. Heber, C. M. S. Cohen, T. Laitinen, I. Cernuda, S. Dalla, F. Espinosa Lara, R. Vainio, M. Köberle, R. Kühl, Z. G. Xu, L. Berger, S. Eldrum, M. Brüdern, M. Laurenza, E. J. Kilpua, A. Aran, A. P. Rouillard, R. Bučík, N. Wijsen, J. Pomoell, R. F. Wimmer-Schweingruber, C. Martin, S. I. Böttcher, J. L. Freiherr von Forstner, J.-C. Terasa, S. Boden, S. R. Kulkarni, A. Ravanbakhsh, M. Yedla, N. Janitzek, J. Rodríguez-Pacheco, M. Prieto Mateo, S. Sánchez Prieto, P. Parra Espada, O. Rodríguez Polo, A. Martínez Hellín, F. Carcaboso, G. M. Mason, G. C. Ho, R. C. Allen, G. Bruce Andrews, C. E. Schlemm, H. Seifert, K. Tyagi, W. J. Lees, J. Hayes, S. D. Bale, V. Krupar, T. S. Horbury, V. Angelini, V. Evans, H. O’Brien, M. Maksimovic, Yu. V. Khotyaintsev, A. Vecchio, K. Steinvall and E. Asvestari A&A, 656 (2021) A20 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112439
Deposited By: George Porter
Deposited On:15 Dec 2021 18:41
Last Modified:16 Dec 2021 19:57

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