A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Shock and SEP Modeling Study for the 2022 September 5 SEP Event
Tekijät: Kouloumvakos, A.; Wijsen, N.; Jebaraj, I. C.; Afanasiev, A.; Lario, D.; Cohen, C. M. S.; Riley, P.; Mitchell, D. G.; Ding, Z.; Vourlidas, A.; Giacalone, J.; Chen, X.; Hill, M. E.
Kustantaja: American Astronomical Society
Kustannuspaikka: BRISTOL
Julkaisuvuosi: 2025
Journal: Astrophysical Journal
Tietokannassa oleva lehden nimi: The Astrophysical Journal
Lehden akronyymi: ASTROPHYS J
Artikkelin numero: 100
Vuosikerta: 979
Numero: 2
Sivujen määrä: 15
ISSN: 0004-637X
eISSN: 1538-4357
DOI: https://doi.org/10.3847/1538-4357/ada0be
Verkko-osoite: https://doi.org/10.3847/1538-4357/ada0be
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/485045508
On 2022 September 5, during Parker Solar Probe's (PSP) 13th encounter, a fast shock wave and a related solar energetic particle (SEP) event were observed as the spacecraft approached the perihelion of its orbit. Observations from the Integrated Science Investigation of the Sun (IS circle dot IS) instrument suite show that SEPs arrived at the spacecraft with a significant delay from the onset of the parent solar eruption and that the first arriving SEPs exhibited an inverse velocity dispersion (IVD) for energetic protons above similar to 1 MeV. Utilizing data from multiple spacecraft, we investigate the eruption dynamics and shock wave propagation. Our analysis includes 3D shock modeling and SEP transport simulations to examine the origins of this SEP event and explore the causes of the delayed SEP onset and the observed IVD. The data-driven SEP simulation reproduces the SEP event onset observed at PSP, its evolving energy spectrum, and the IVD. This IVD is attributed to a relatively slow, ongoing particle acceleration process occurring at the flank of the expanding shock wave intercepted by PSP. This has significant implications for the role of shocks in the release of SEPs at widespread events and for methods used to infer the SEP release times. Furthermore, the match between the simulation and observations worsens when cross-field diffusion is considered, indicating that SEP diffusion had a minor effect on this event. These findings underscore the complexity of SEP events and emphasize the need for advanced modeling approaches to better understand the role of shock waves and other physical processes in SEP acceleration and release.
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The authors would like to thank the anonymous reviewer for providing thoughtful and constructive comments, which helped to improve the quality of this paper. A.K. acknowledges financial support from NASA NNN06AA01C (PSP EPI-Lo) contract. N.W. acknowledges funding from the Research Foundation—Flanders (FWO—Vlaanderen, fellowship No. 1184319N) and from the KU Leuven project 3E241013. A.A. acknowledges funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 101004159 (SERPENTINE) as well as from the Finnish Centre of Excellence in Research of Sustainable Space (FORESAIL) funded by the Research Council of Finland (grant No. 336809). I.C.J is grateful for support from the Research Council of Finland (SHOCKSEE, grant No. 346902) and the European Union's (E.U's) Horizon 2020 research and innovation program under grant agreement No. 101134999 (SOLER). The study reflects only the authors' view, and the European Commission is not responsible for any use that may be made of the information it contains. Computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Centre), funded by the FWO and the Flemish Government-Department EWI. Parker Solar Probe was designed, built, and is now operated by the Johns Hopkins Applied Physics Laboratory (JHU/APL) as part of NASA's Living with a Star (LWS) program (contract NNN06AA01C). We thank the STEREO: SECCHI SOHO: LASCO; SDO/AIA teams and Predictive Science Inc. 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 used are courtesy of SDO (NASA) and the AIA consortium. Some data processing for this research was carried out using version 5.1.0 (Mumford et al. 2020) of the SunPy open-source software package (SunPy Community 2020). This research has made use of PyThea v0.11.0, an open-source and free Python package to reconstruct the 3D structure of CMEs and shock waves (A. Kouloumvakos 2022b).
