An Overview of Solar Orbiter Observations of Interplanetary Shocks in Solar Cycle 25
: Trotta, Domenico; Dimmock, Andrew; Hietala, Heli; Blanco-Cano, Xochitl; Horbury, Timothy S.; Vainio, Rami; Dresing, Nina; Jebaraj, Immanuel Christopher; Lara, Francisco Espinosa; Gomez-Herrero, Raul; Rodriguez-Pacheco, Javier; Kartavykh, Yulia; Lario, David; Gieseler, Jan; Janvier, Miho; Maksimovic, Milan; Sheshvan, Nasrin Talebpour; Owen, Christopher J.; Kilpua, Emilia K. J.; Wimmer-Schweingruber, Robert F.
Publisher: IOP Publishing Ltd
: BRISTOL
: 2025
: Astrophysical Journal Supplement
: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
: ASTROPHYS J SUPPL S
: 2
: 277
: 1
: 17
: 0067-0049
: 1538-4365
DOI: https://doi.org/10.3847/1538-4365/ada4a7
: https://doi.org/10.3847/1538-4365/ada4a7
: https://research.utu.fi/converis/portal/detail/Publication/484755054
Interplanetary (IP) shocks are fundamental constituents of the heliosphere, where they form as a result of solar activity. We use previously unavailable measurements of IP shocks in the inner heliosphere provided by Solar Orbiter, and present a survey of the first 100 shocks observed in situ at different heliocentric distances during the rising phase of solar cycle 25. The fundamental shock parameters (shock normals, shock normal angles, shock speeds, compression ratios, Mach numbers) have been estimated and studied as a function of heliocentric distance, revealing a rich scenario of configurations. Comparison with large surveys of shocks at 1 au shows that shocks in the quasi-parallel regime and with high speed are more commonly observed in the inner heliosphere. The wave environment of the shocks has also been addressed, with about 50% of the events exhibiting clear shock-induced upstream fluctuations. We characterize energetic particle responses to the passage of IP shocks at different energies, often revealing complex features arising from the interaction between IP shocks and preexisting fluctuations, including solar wind structures being processed upon shock crossing. Finally, we give details and guidance on the access use of the present survey, available on the EU-project "Solar Energetic Particle Analysis Platform for the Inner Heliosphere" website. The algorithm used to identify shocks in large data sets, now publicly available, is also described.
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This study has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 101004159 (SERPENTINE, https://serpentine-h2020.eu/). Views and opinions expressed are, however, those of the authors only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. This work was supported by the UK Science and Technology Facilities Council (STFC) grant ST/W001071/1. Solar Orbiter magnetometer operations are funded by the UK Space Agency (grant ST/X002098/1). Solar Orbiter is a space mission of international collaboration between ESA and NASA, operated by ESA. Solar Orbiter SWA data are derived from scientific sensors that have been designed and created and are operated under funding provided in numerous contracts from the UK Space Agency (UKSA), the UK STFC), the Agenzia Spaziale Italiana (ASI), the Centre National d'Etudes Spatiales (CNES, France), the Centre National de la Recherche Scientifique (CNRS, France), the Czech contribution to the ESA PRODEX program and NASA. Solar Orbiter SWA work at UCL/MSSL is currently funded under STFC grants ST/W001004/1 and ST/X/002152/1. EPD on Solar Orbiter is supported by the Spanish Ministerio de Ciencia, Innovación y Universidades FEDER/MCIU/AEI Projects ESP2017-88436-R and PID2019-104863RB-I00/AEI/10.13039/501100011033 and the German space agency (DLR) under grant 50OT2002. X.B.C. acknowledges DGAPA PAPIIT grant IN106724 and CONAHCyT grant CBF2023-2024-852 H.H. is supported by the Royal Society University Research Fellowship URF R1 180671. N.D. is grateful for the support from the Academy of Finland (SHOCKSEE, grant No. 346902). T.S.H. is supported by STFC grant ST/W001071/1.
