Important advances in the observation and modeling of energetic phenomena have been made possible by the development of multi-messenger and time-domain astronomy. However, the origin of high-energy cosmic rays remains mysterious. Deciding between the various candidate sources requires a precise modeling of the propagation, acceleration and interactions of cosmic rays.

Due to their huge rotational energy and large magnetic fields, pulsars have been proposed as candidate sources of high-energy cosmic rays. In this context, we demonstrate that a population of pulsars in the galactic center region could explain the diffuse gamma-ray emission detected by HESS. Using particle-in-cell simulations, we focus on cosmic-ray acceleration in pulsar magnetosphere, and show that accelerated ions can escape from these environments.