Energetic Solar Eruptions: Data and Analysis Tools

Project Information

SOLER

Grant agreement ID: 101134999

DOI

10.3030/101134999

EC signature date 16 November 2023

Start date 1 January 2024

End date 28 February 2027

Funded under

• Digital, Industry and Space

Total cost

€ 1 496 838,75

EU contribution

€ 1 496 838,75

Coordinated by

TURUN YLIOPISTO
Finland

Periodic Reporting for period 1 - SOLER (Energetic Solar Eruptions: Data and Analysis Tools)

Reporting period: 2024-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

The Energetic Solar Eruptions: Data and Analysis Tools (SOLER) project will investigate the most energetic phenomena occurring at the Sun and provide new knowledge on their interrelations, variability and energy partitioning. Using the newly expanded unprecedented heliospheric spacecraft fleet, including ESA's Solar Orbiter and NASA's Parker Solar Probe, we will investigate energetic solar eruptions starting from three perspectives: fast coronal mass ejections (CMEs), strong X-ray flares, and large solar energetic particle (SEP) events. Key parameters of the various eruption phenomena will be determined and their interrelations examined to make significant leaps in our understanding on how the eruptive phenomena are linked to each other, how they interact with each other, and how they result in acceleration and release of high energy particles from the solar corona into interplanetary (IP) space. Because of their direct link to particle energisation, large-amplitude coronal waves and shocks related to these events will be in focus as well. Magnetic connections of sources with each other and with the in-situ observers will be determined. In addition to producing significant amounts of new scientific knowledge in the field, SOLER will provide the wider scientific community a wide array of advanced data products, and novel data analysis and visualisation tools that will be openly distributed. This will greatly facilitate future interdisciplinary studies of energetic solar eruptions.

The main scientific objective of SOLER is to provide answers to the following three science questions:

Q1: Connections. What are the magnetic connections between EM radiation sources in the low corona (X-ray) and in the high corona (radio) and how are they connected to the particle radiation observed in situ?

Q2: Relations. What are the relations between the properties of the in-situ SEP observations (energy spectra, time profiles, anisotropies, composition) and the source characteristics (flare X-ray spectra, time profiles, composition; shock parameters) and between the source characteristics themselves?

Q3: Variability. What are the reasons for the large variations in SEP properties and associated flare and CME characteristics (including the presence of non-events in case of strong flares and/or fast CMEs)?

Related to these scientific questions, SOLER has three technical objectives as follows:

T1: Catalogues. SOLER will deliver three interlinked catalogues of energetic solar phenomena consisting of strong flares, fast CMEs and large SEP events.

T2: Analysis tools. SOLER will deliver new tools for analysing and visualising solar eruption datasets and modelling results in an integrated manner and distribute them openly to the scientific community.

T3: Data. SOLER will produce several high-level multi-instrument datasets and distribute them openly to the scientific community.

To achieve these objectives, the work is divided in seven scientific and technical work packages addressing the development of analysis methodologies (WP2-WP6), scientific data analysis (WP7) and distribution of data and tools (WP8).

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The work in SOLER is broken into three main phases,
- Detailed planning phase (Months 1–6)
- Main analysis phase (Months 7–36)
- Wrap–up (Months 37–38)
The Detailed planning phase was completed in Month 6 and culminated in the SOLER User Requirements Workshop organised in the University of Helsinki (19–20 June 2024), where members of the heliophysics community could give comments on the planning of the project. The submission of the detailed plans for each WP related to analysis methodologies followed, after taking this user feedback into account. Thereafter the work on the actual methodology development has commenced.

In terms of addressing the science questions, the work in SOLER has started. We have carried on with the analyses utilising the fleet of inner heliospheric spacecraft that were started in the preceding H2020/SERPENTINE project. The team has presented, for the first time, direct measurements of synchrotron-emitting electrons at shocks (Jebaraj et al. 2024, ApjL, doi:10.48550/arXiv.2410.15933) a study that directly contributes to science questions Q1 and Q2. We have also completed a statistical study of 45 SEP events, started during H2020/SERPENTINE, linking the properties of solar eruptions and SEPs (Farwa et al. 2025, A&A, doi:10.1051/0004-6361/202450945) that contributes to Q3. Altogether 18 scientific papers have already been published on the SOLER analysis tools and science. In terms of technical objectives, the team has already established the platform for SOLER analysis tools (SERPENTINE-SOLER Jupyter Hub). Most of the tools have already been developed and released in GitHub for the community as well as in the SOLER Jupyter Hub. The work on the interlinked catalogues is well underway.

The second major event organised by the project was the SOLER User Workshop in June 2025 in Paris Observatory / Meudon. It was a hybrid meeting with more than 40 participants, presenting first scientific results from the project as well as the tools developed during the first half of the project.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Tools developed and released represent clear steps forward in the analysis of solar eruptions (e.g. Palmroos et al. 2025, A&A, doi:10.1051/0004-6361/202451280) and coronal and heliospheric magnetic connectivities (e.g. https://solar-mach-pfss.streamlit.app/). The NenuSun tool (https://nenusun.obspm.fr/catalogue/) already provides access to the novel NenuFAR data on the Sun. Scientific results on widespread SEP events (e.g. Rodríguez-Garcíaet al. 2025, A&A, doi:10.1051/0004-6361/202452158; Dresing et al. 2025, A&A, doi:10.1051/0004-6361/202453596) have provided clear evidence on the dominant role of shock waves in the spreading of energetic particles in the interplanetary medium, explaining events that can reach even circumsolar extend in heliolongitude.