The main goal of our focused science team is to obtain a comprehensive picture of wave propagation in the lower solar atmosphere, from the generation of waves in sub-photospheric layers to their channelling and eventual dissipation in the magnetised outer atmosphere. In particular, the focus is on various, and often coupled, wave modes propagating through structures with a wide range of sizes and physical properties, which can only be probed using the highest-resolution imaging and spectro-polarimetric observations currently available. These studies are expected to provide insight into the coupling mechanisms between individual wave modes, as well as reliable estimates of the energy transported by MHD waves into the upper solar atmosphere, thereby shedding light on the dissipation mechanisms of these waves and hence their contribution to heating the outer layers of the solar atmosphere. These investigations will be carried out using high-resolution observations interpreted in tandem with theoretical models and numerical simulations.
Below we identify the key objectives of our current projects, which aim to address the following:
The subsurface generation of waves (e.g., how coherence and amplitudes may vary across features within the same field of view, and how these measurements can be used to uncover information related to sub-photospheric structuring)
Subsequent mode coupling (e.g., determining where such favourable conditions exist and how efficient such mechanisms are)
Whether multiple modes regularly coexist within certain structures (e.g., sunspots, pores, magnetic bright points, spicules, fibrils, and filaments)
The prevalence of shock formation in the lower atmosphere (not only acoustic shocks, but also intermediate and possibly Alfvénic nonlinearities)
How energy is reflected (i.e., superimposed again on the photospheric observations), damped, and/or dissipated in the form of atmospheric heating
A direct comparison of high-resolution observations with state-of-the-art numerical simulations and theoretical models, such as those provided by the Bifrost, MURaM, CO5BOLD, Mancha, and LARExD codes; and
How asymmetric spectro-polarimetric signatures can be influenced by resolved, and potentially unresolved, wave activity
To address these challenges fully, we must employ spectropolarimetric data. This will allow us to determine properties such as magnetic field and line-of-sight velocity as a function of height in our observations. These diagnostics can then be used in tandem with observations of the transition region and corona. By using spectropolarimetric data, we can also compare our results more directly with state-of-the-art numerical simulations and theoretical models.