Whitepaper #229 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: space weather applications; basic research. Additional topics: ground-based missions/projects; solar physics; other space weather.
The coronal magnetic field is the main actor in the physics of the solar corona and of activity events generating Space Weather, but our measurements are sporadic, lack accuracy and can’t cover the entire corona. We advocate for a ground based instrument (COSMO-LC) capable of measuring at the same time the coronal magnetic field and plasma properties simultaneously over the whole solar corona.