High resolution solar ALMA imaging

Solar ALMA scientific observations has been enabled - with our contribution - since ALMA Cycle 4 in 2017. Nevertheless, the solar observing mode has been, due to many peculiarities of the Sun as a source at mm wavelengths, subject to many limitations in comparison to the 'standard' observations. Among those, which are perceived as one of the most pressing by the community, it is the restriction for maximum allowed array configuration, which implies rather severe constrains for spatial resolution in solar ALMA observations.

In order to overcome these limitations, a couple of changes in observing setup (timing, alternative phase-correction methods) and data post-processing have been proposed for solar observations and they are currently (since October 2022) in-depth investigated in frame of another ESO ALMA Development Study - High resolution solar ALMA imaging. It is an international-collaboration project led by the Czech ARC node. The work is beyond its mid-point and the project has already passed the mid-term review in 2024. Work-progress and the results reached insofar are summarised in the Mid-term project report.