Large Field-of-View Spectropolarimetric Observations with a Large Aperture Telescope

In the context of the increasing interest in large-aperture telescopes dedicated to the Sun, we present a study to evaluate the adaptive-optics system limitations on the requirements expected for magnetic-field extrapolations and data-driven MHD simulations of active regions. The questions we address include: What is the size of the field of view at high spatial resolution for a four-meter class telescope with a spectrograph? What is the impact of the selected spectral domain on the performance in relation to the aforementioned scientific goals? We show that the visible-wavelength domain remains difficult to explore with ground-based telescopes using classical adaptive optics systems. The field of view obtained will be only a few arcseconds at the diffraction limit for most of the time. We review alternative configurations of adaptive-optics systems for different telescope apertures and wavelength domains which could be considered for practical implementation in derivations of the magnetic field from polarimetric observations.