Revealing cosmic magnetism in the near future: new insights from the radio sky

The last decade represented a breakthrough in the study of cosmic magnetism, from our Galaxy to the large-scale structure of the Universe. The unprecedented amount and quality of polarization data across the electromagnetic spectrum started shedding light on the tight coupling between magnetic fields and interstellar matter. A new observational window is now open to understand the role of magnetic fields in the dynamical evolution of galaxies and star formation. Thanks to the growing development of ground-based interferometric facilities at radio frequencies – e.g., LOFAR, NenuFAR, CHIME, DRAO, Parkes, MWA, and the Square Kilometer Array with its precursors -- synchrotron radiation resulting from the interaction of cosmic-ray electrons with magnetic fields is today the best-suited spotlight to enlighten the mystery of cosmic magnetism. However, the ability of linking the large amount of radio data that will be soon achieved with cosmic magnetism will strongly depend upon our limited knowledge of paramount problems, from the accurate description of cosmic-ray physics to the ionization mechanisms across gas phases in the dynamical interstellar and intergalactic media. This motivates the need of bringing together experts of both radio-polarimetric observations and theory of magnetism and cosmic rays with the purpose of triggering discussions and fostering collaborations that will enable the community to steadily advance and address fundamental questions, e.g. what is responsible for magnetic-field amplification and evolution in galaxies? What is the impact of magnetic fields on structure formation in the universe? Thanks to the support of the Action Specifique CNRS SKA-LOFAR (https://as-ska-lofar.fr/#science), we are organizing a second hybrid workshop that will be held in the center of Paris at the École Normale Supérieure on October 26 - 27, 2023. The meeting will focus on five main topics: Galactic radio observations; extragalactic radio observations; theory of magnetized processes in the Galaxy; theory of magnetized processes in the large-scale structure of the universe; Cosmic ray physics. Our goal will be to let the five communities discuss, interact, and exchange knowledge and tools. We welcome contributions from observers and modelers of galactic and intergalactic magnetism, in particular in the context of the upcoming SKA.