Solar Orbiter’s Far-side Magnetogram Impacts on Coronal Holes and Solar Wind Predictions

Abstract We investigate the impact of Solar Orbiter's far-side magnetic field observations on coronal holes and solar wind predictions at multiple heliospheric locations during the period of 2024 March 30–May 21. Far-side data, obtained from the Polarimetric and Helioseismic Imager on board Solar Orbiter, were incorporated into the Air Force Data Assimilative Photospheric Flux Transport Helioseismic and Magnetic Imager maps and used as input to the Wang–Sheeley–Arge model (v6.2). Solar wind predictions produced with and without the inclusion of far-side magnetogram information were compared against in situ measurements from Solar Orbiter, ACE, STEREO-A, and Parker Solar Probe. Time intervals where the two simulations differ substantially were identified and such differences were related to changes in coronal hole morphology and magnetic connectivity driven by the assimilation of far-side data. Results highlighted here demonstrate that far-side observations can significantly improve solar wind predictions not only near Solar Orbiter but also at locations up to 165° away in heliographic longitude, as demonstrated at ACE's location. We further show that far-side data can lead to notable changes in the modelled polarity of the coronal magnetic field and the shape of the heliospheric current sheet through magnetic flux redistribution. These findings underscore the importance of incorporating far-side observations into global models and highlight their potential to improve both background solar wind and coronal mass ejection modeling for enhanced space weather forecasting throughout the inner heliosphere.