Solar Orbiter

HipFT model result(SDO assimilation region plus later SO view and assimilated regions are indicated)
SO/EUI/FSI 174 Å Channel(EUV emission, Radially Filtered)
SO/MetisK-Corona Brightness, Radially Filtered
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The 2026 Total Solar Eclipse presents a new opportunity to test how magnetic field observations on the far side of the Sun can improve predictions of coronal structure. If we were using a traditional synoptic map of the solar magnetic field, the east limb of the Sun (as viewed from Earth) would have some of the oldest magnetic data. On Eclipse day (August 12), the data on the east limb would be derived from observations on July 23 - the data would be “stale.”

For this eclipse, Solar Orbiter (SO) is on the solar far side in the days and weeks leading up to the eclipse, moving close to the east limb on Eclipse day. Thanks to coordination and special efforts by the team operating the SO PHI instrument, we expect to assimilate magnetograms from the full-disk vector magnetograph (FDT) beginning on August 1.

In the animation shown on the left, the green and purple circles indicate the ±60° field-of-view from SDO and SO respectively. These are the approximate assimilation windows for magnetic data from HMI and PHI. This will provide an unprecedented opportunity to model coronal structures on the solar east limb with updated, “fresh” data during a total solar eclipse. This will also give us a preview of how future observations from the Vigil mission (set to launch in 2031) may improve future space weather forecasts.

The middle panel shows EUV emission synthesized for the 174 Å channel of the Full Sun Imager (FSI), which is part of the Extreme Ultraviolet Imager (EUI) onboard SO. Like the imaging observations on the EUV and X-ray page, the FSI channels are sensitive to coronal plasma in particular temperature ranges ( ∼ ⁣\sim\! 1 MK in this case). Unique to FSI is the extremely large field of view (±\pm 1.9∘^\circ), which captures the extended solar corona at EUV wavelengths, and provides a global picture of the Sun no-matter what distance SO is from the Sun.

The right panel shows the view of the corona from the SO/Metis coronagraph, which is also shown on the coronagraphs page. The white circle indicates the solar surface. Similar to EUI/FSI, as time progresses this circle will grow larger as SO moves closer to the Sun.

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ACKNOWLEDGEMENTS

This research is funded by NASA and NSF. We are grateful to Instituto de Astrofísica de Canarias (IAC) for providing a dedicated allocation at the LaPalma supercomputer and proud to support the North African Telescope Eclipse (NATE) project, led by IAC. We also acknowledge dedicated resources from the ACCESS program and Expanse supercomputer at the San Diego Supercomputer Center (SDSC). We thank NASA's Advanced Supercomputing Division (NAS) for allocations on the Athena supercomputer that enabled many of the visualizations on this page to be produced rapidly in real-time. We also thank the SDO/HMI team of the Solar Physics Group at Stanford University for their support in providing timely access to HMI vector magnetograph data. Lastly, we are particularly excited to work with the Solar Orbiter PHI team, to conduct the farside assimilation experiment in near-real-time.