Hybrid Simulations of Acceleration of Heavy Nuclei at Non-Relativistic Shocks

We investigate the diffusive shock acceleration of particles with mass to charge ratio, A/Q > 1. We introduce He- and C-like particles at solar abundances into 2D hybrid (kinetic ions/fluid electrons) simulations of non-relativistic collisionless shocks.

We find that particles with large A/Q ratios are preferentially accelerated over protons; for typical solar abundance, the energy that goes in accelerated He is comparable or larger than the one in protons, increasing the total shock acceleration efficiency. Moreover, accelerated He nuclei contribute to amplify the magnetic field, which leads to a larger maximum energy. These effects should be reckoned with in the phenomenology of sources such as supernova remnants and heliospheric shocks.