  In the context of the INFN project PANDORA_Gr3 (Plasma for Astrophysics,
Nuclear Decays Observation and Radiation for Archaeometry) and of
multi-messenger astronomy, we propose a feasibility study for in-laboratory
plasma's opacity investigation, in an environment resembling thermodynamic
conditions typical of the ejecta of compact binary mergers containing at least
a neutron star. We aim to advance knowledge on the physics of kilonovae, the
electromagnetic transients following a merger, which are relevant for the study
of the origin of heavy nuclei in the Universe produced via r-process
nucleosynthesis. In this paper, we present preliminary results of numerical
simulations for some physics cases considered in the light of a possible
experimental setup for future in-laboratory opacity spectroscopic measurements.
