Research project P4S/251/PRALINE (Research action P4S)
The ESA Solar Orbiter mission marks a historic leap in heliophysics, providing the first high-resolution, non-ecliptic perspectives of the Sun’s poles.
A cornerstone instrument on Solar Orbiter is the Extreme Ultraviolet Imager (EUI), which includes the High Resolution Imager in the EUV (HRIEUV) and the Full Sun Imager (FSI). Together, these telescopes deliver the most detailed sequences of the solar corona ever captured: HRIEUV offering the highest spatial resolution to date, while FSI provides the widest field of view ever achieved in this wavelength range. PRALINE will leverage this unprecedented out-of-ecliptic dataset to investigate the physics of the Sun’s polar regions and understand their connection to large-scale structures in the heliosphere.
Scientific objectives
- Bridging the Ulysses Legacy: While the Ulysses mission identified unexpected magnetic field configurations at high latitudes, it lacked imaging. PRALINE uses EUI’s visual data alongside in-situ measurements to link polar source regions to solar wind dynamics.
- Small-Scale Dynamics: Recent EUI data from the ecliptic plane have uncovered unprecedented phenomena, including the smallest EUV brightenings ever seen and high-frequency transverse waves. By observing from high latitudes, we eliminate the heavy foreshortening that typically distorts polar data.
- Polar Structure & Evolution: We will track coronal hole boundaries, plumes, and bright points from high latitudes to refine solar dynamo models and understand polar differential rotation.
While the focus of this project is on non-ecliptic EUI data, it will be supported by other instruments. For the first time, a coordinated constellation of observatories enables a comprehensive, multi-perspective study of the solar poles and their heliospheric connections.
This project brings together a team of experts who are uniquely positioned to apply existing methods to this new class of data as it becomes available over the next several years. The PRALINE project is conceived as a pathfinder and proof-of-concept for the scientific value of non-ecliptic EUV imaging, and will actively promote broader community engagement. A strong commitment to open-access principles for all data products, methodologies, and results will ensure maximum impact, reproducibility, and reuse by the broader heliophysics community.
