Limiting the shock acceleration of cosmic-ray protons in the ICM
  Observations of large-scale radio emissions prove the existence of shock
accelerated cosmic-ray electrons in galaxy clusters, while the lack of detected
$\gamma$-rays limits the acceleration of cosmic-ray protons in galaxy clusters.
This challenges our understanding of how diffusive shock acceleration works. In
this work, we couple the most updated recipes for shock acceleration in the
intracluster medium to state-of-the-art magneto-hydrodynamical simulations of
massive galaxy clusters. Furthermore, we use passive tracer particles to follow
the evolution of accelerated cosmic-rays. We show that when the interplay
between magnetic field topology and the feedback from accelerated cosmic rays
is taken into account, the latest developments of particle acceleration theory
give results which are compatible with observational constraints.
