The region between the mainly magnetically closed inner corona and the mostly radial outer corona–the middle corona– is largely unexplored in long-term data-sets, despite the fact that important, but unknown, physical processes and transitions, which accelerate the solar wind and affect the inner corona are acting there. Studies have relied on sporadic off-point campaigns from space-based instrumentation and ground-based eclipse observations.

Several space-based missions aim to soon fill this observational gap. However, obtaining information on the plasma state (such as densities, temperatures, velocities, magnetic field, and chemical abundances) is a non-trivial task.

We have gathered a range of leading experts to assess/compare forward modelling techniques and benchmark them against observations to obtain such information. Emphasis is on 1) 3-D codes for the calculation of spectral line intensities taking into account resonant photo-excitation and Doppler dimming effects; 2) 3-D codes for the calculation of the Stokes profiles including the magnetic field, estimated from global MHD simulations. 

We will also coordinate multi-wavelength campaigns and recommend future observations and  missions.


We acknowledge the use of Zulip for communicating among the team members. Zulip is an open-source modern team chat app designed to keep both live and asynchronous conversations organized, see https://zulip.com/