Galaxy clusters as the Universe’s largest particle accelerators

Mergers of galaxy clusters represent the most energetic events since the Big Bang, releasing energies up to 10^64 ergs over Gyr timescales. This energy is dissipated through shocks and turbulence in the intracluster medium, transforming clusters into the Universe’s largest laboratories for studying cosmic ray acceleration and magnetic field amplification. However, our understanding has largely been limited to massive and nearby clusters due to observational constraints. In this talk, I will show how observations at the longest wavelengths observable from the ground are revealing new insights into both turbulence and magnetic field amplification. Additionally, I will discuss how advances in radio polarimetry and new surveys such as POSSUM are revealing the first detailed magnetic field structures within individual clusters.