eprintid: 10205891
rev_number: 6
eprint_status: archive
userid: 699
dir: disk0/10/20/58/91
datestamp: 2025-03-11 14:11:36
lastmod: 2025-03-11 14:11:36
status_changed: 2025-03-11 14:11:36
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Rodriguez-Garcia, L
creators_name: Gomez-Herrero, R
creators_name: Dresing, N
creators_name: Balmaceda, LA
creators_name: Palmerio, E
creators_name: Kouloumvakos, A
creators_name: Jebaraj, IC
creators_name: Espinosa Lara, F
creators_name: Roco, M
creators_name: Palmroos, C
creators_name: Warmuth, A
creators_name: Nicolaou, G
creators_name: Mason, GM
creators_name: Guo, J
creators_name: Laitinen, T
creators_name: Cernuda, I
creators_name: Nieves-Chinchilla, T
creators_name: Fedeli, A
creators_name: Lee, CO
creators_name: Cohen, CMS
creators_name: Owen, CJ
creators_name: Ho, GC
creators_name: Malandraki, O
creators_name: Vainio, R
creators_name: Rodriguez-Pacheco, J
title: Solar energetic particles injected inside and outside a magnetic cloud
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F63
keywords: Sun: corona / Sun: coronal mass ejections (CMEs) / Sun: flares / Sun: heliosphere / Sun: particle emission
note: © The Authors 2025. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
abstract: Context. On 2022 January 20, the Energetic Particle Detector (EPD) on board Solar Orbiter measured a solar energetic particle (SEP) event showing unusual first arriving particles from the anti-Sun direction. Near-Earth spacecraft separated by 17 in longitude to the west of Solar Orbiter measured classic anti-sunward-directed fluxes. STEREO-A and MAVEN, separated by 18 to the east and by 143 to the west of Solar Orbiter, respectively, also observed the event, suggesting that particles spread over at least 160 in the heliosphere. Aims. The aim of the present study is to investigate how SEPs are accelerated and transported towards Solar Orbiter and near-Earth spacecraft, as well as to examine the influence of a magnetic cloud (MC) present in the heliosphere at the time of the event onset on the propagation of energetic particles. Methods. We analysed remote-sensing data, including flare, coronal mass ejection (CME), and radio emission to identify the parent solar source of the event. We investigated energetic particles, solar wind plasma, and magnetic field data from multiple spacecraft. Results. Solar Orbiter was embedded in a MC erupting on 16 January from the same active region as that related to the SEP event on 20 January. The SEP event is related to a M5.5 flare and a fast CME-driven shock of ∼1433 km s-1, which accelerated and injected particles within and outside the MC. Taken together, the hard SEP spectra, the presence of a Type II radio burst, and the co-temporal Type III radio burst being observed from 80 MHz that appears to emanate from the Type II burst, suggest that the shock is likely the main accelerator of the particles. Conclusions. Our detailed analysis of the SEP event strongly suggests that the energetic particles are mainly accelerated by a CME-driven shock and are injected into and outside of a previous MC present in the heliosphere at the time of the particle onset. The sunward-propagating SEPs measured by Solar Orbiter are produced by the injection of particles along the longer (western) leg of the MC still connected to the Sun at the time of the release of the particles. The determined electron propagation path length inside the MC is around 30% longer than the estimated length of the loop leg of the MC itself (based on the graduated cylindrical shell model), which is consistent with the low number of field line rotations.
date: 2025-02-04
date_type: published
publisher: EDP SCIENCES S A
official_url: https://doi.org/10.1051/0004-6361/202452158
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2365753
doi: 10.1051/0004-6361/202452158
lyricists_name: Owen, Christopher
lyricists_name: Nicolaou, Georgios
lyricists_id: CJOWE13
lyricists_id: GNICO14
actors_name: Owen, Christopher
actors_id: CJOWE13
actors_role: owner
funding_acknowledgements: [European Space Agency (ESA) research fellowship programme]; [Spanish Ministerio de Ciencia, Innovacion y Universidades FEDER/MCIU/AEI]; 101134999 [European Union]; 346902 [Research Council of Finland]; 80NSSC19K0069 [NASA program NNH17ZDA001N-LWS]; 80NSSC19K1235 [NASA program NNH17ZDA001N-LWS]; 80NSSC19K0067 [NASA]; 80NSSC22K0893 [NASA]; NNN06AA01C [NASA]; 346902 [Academy of Finland]; 50 OT 2304 [German Space Agency (DLR)]; 42188101 [National Natural Science Foundation of China]; 42130204 [National Natural Science Foundation of China]; 42474221 [National Natural Science Foundation of China]; ST/V000934/1 [UK Science and Technology Facilities Council (STFC)]; ST/Y002725/1 [UK Science and Technology Facilities Council (STFC)]; 80NSSC21K1325 [NASA LWS program]; [MAVEN project through the NASA Mars Exploration Program]; [Research Council of Finland]; ESP2017-88436-R; PID2019-104863RB-I00/AEI; 101004159; 352847
full_text_status: public
publication: Astronomy & Astrophysics
volume: 694
article_number: A64
pages: 29
issn: 0004-6361
citation:        Rodriguez-Garcia, L;    Gomez-Herrero, R;    Dresing, N;    Balmaceda, LA;    Palmerio, E;    Kouloumvakos, A;    Jebaraj, IC;                                                                         ... Rodriguez-Pacheco, J; + view all <#>        Rodriguez-Garcia, L;  Gomez-Herrero, R;  Dresing, N;  Balmaceda, LA;  Palmerio, E;  Kouloumvakos, A;  Jebaraj, IC;  Espinosa Lara, F;  Roco, M;  Palmroos, C;  Warmuth, A;  Nicolaou, G;  Mason, GM;  Guo, J;  Laitinen, T;  Cernuda, I;  Nieves-Chinchilla, T;  Fedeli, A;  Lee, CO;  Cohen, CMS;  Owen, CJ;  Ho, GC;  Malandraki, O;  Vainio, R;  Rodriguez-Pacheco, J;   - view fewer <#>    (2025)    Solar energetic particles injected inside and outside a magnetic cloud.                   Astronomy & Astrophysics , 694     , Article A64.  10.1051/0004-6361/202452158 <https://doi.org/10.1051/0004-6361%2F202452158>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10205891/1/Rodriguez_et_al_aa52158-24.pdf