  Magnetism defines the complex and dynamic solar corona. Coronal mass
ejections (CMEs) are thought to be caused by stresses, twists, and tangles in
coronal magnetic fields that build up energy and ultimately erupt, hurling
plasma into interplanetary space. Even the ever-present solar wind possesses a
three-dimensional morphology shaped by the global coronal magnetic field,
forming geoeffective corotating interaction regions. CME evolution and the
structure of the solar wind depend intimately on the coronal magnetic field, so
comprehensive observations of the global magnetothermal atmosphere are crucial
both for scientific progress and space weather predictions. Although some
advances have been made in measuring coronal magnetic fields locally, synoptic
measurements of the global coronal magnetic field are not yet available.
  We conclude that a key goal for 2050 should be comprehensive, ongoing 3D
synoptic maps of the global coronal magnetic field. This will require the
construction of new telescopes, ground and space-based, to obtain
complementary, multiwavelength observations sensitive to the coronal magnetic
field. It will also require development of inversion frameworks capable of
incorporating multi-wavelength data, and forward analysis tools and simulation
testbeds to prioritize and establish observational requirements on the proposed
telescopes.
