Harra, L. ; Barczynski, K. ; Auchère, F. ; Berghmans, D. ; Chitta, L. P. ; Parenti, S. ; Peter, H.

published in Space Science Reviews, 221 , pp. article number 50 (2025)

Abstract: The quiet Sun corona and coronal holes, as seen in the extreme ultraviolet (EUV), host a variety of phenomena that operate over a range of spatial and temporal scales. Dynamic brightenings and jets of at most a few megameters appear to evolve on minute timescales. Coronal structures larger than tens of Mm evolve on much longer, hour timescales. Un- derstanding the characteristics of the quiet Sun corona and coronal holes along with their disparate phenomena will provide important constraints on models that aim to explain how the plasma is heated and how it further expands to form the solar wind. In 2020, the Euro- pean Space Agency (ESA) Solar Orbiter mission was launched. It features a comprehensive remote-sensing package, which includes two instruments observing in the Extreme Ultravi- olet (EUV) and UV spectrometer data: the Extreme Ultraviolet Imager (EUI) that provides high resolution Extreme Ultraviolet (EUV) images at 174 Å (HRIEUV), and the Spectral Imaging of the Coronal Environment (SPICE) spectrometer that enables plasma diagnos- tics, and the Polarimetric and Helioseismic Imager (PHI) that measures the photospheric magnetic field. These data, alongside a fleet of instruments on the Solar Dynamics Observa- tory (SDO), Hinode and the Interface Region Imaging Spectrograph (IRIS), are providing new information on the behaviour and dynamics of the quiet Sun and coronal holes. We will review the latest results and put them in context of describing the physics of coronal heating and solar wind formation.

Keyword(s): Solar Orbiter ; Quiet Sun ; Extreme Ultraviolet ; Coronal heating ; Solar Wind
DOI: 10.1007/s11214-025-01177-3
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