The Unique and Essential Benefits of a High-Latitude Vantage Point

Largely confined to the ecliptic, our view of the Sun and inner heliosphere is biased by what we can reliably observe. Ulysses provided the first in situ measurements of the high-latitude heliosphere a quarter century ago. Now we are close to having a direct view of the Sun, corona, and inner heliosphere from Solar Orbiter and other proposed high-latitude missions. The most obvious benefit of a polar perspective is the simple capability to see the poles well for the first time. Having dramatically foreshortened observations of just one pole or the other limits what we can measure at the surface and below. Simultaneous good-resolution views of the Sun's entire polar regions in magnetic field and intensity at various wavelengths and temperatures, even one at a time, will help reveal the configuration and evolution of features, as well as the magnetic and velocity fields that are associated with the solar cycle. Interpretations of acoustic waves observed from high latitude will allow us to plumb the depths of the mysterious zone beneath the polar coronal holes. Accurate measurements of the photospheric magnetic field at high latitude will help resolve long-standing deficiencies in our modeling of the solar wind. From far above the ecliptic, comprehensive views of the global low-latitude corona and heliosphere will provide the first truly three-dimensional view of long-lived structures and of the dynamic events that disturb them. And they will complete our picture of how disturbances are linked across hemispheric scales. Combined with contemporary and historic observations from Earth and space-based solar observations, the secrets of the global Sun will be revealed for the first time.