Szczegóły publikacji

Cosmic ray acceleration to high energies in galaxy clusters is still an open question. Relativistic electrons are produced at merger shocks, forming the so-called radio relics that emit synchrotron radiation. These large-scale shocks are also considered to be sources of high-energy cosmic rays and associated gamma-rays and neutrinos. We report on our recent studies of electron acceleration at merger shocks that have low Mach numbers and propagate in hot intracluster medium. Our recent PIC simulation results show that in these conditions, electron acceleration can be provided by the process of stochastic shock-drift acceleration that is facilitated through multi-scale turbulence in the shock, including the ion-scale shock surface rippling. Building upon these studies here we present results obtained with a newly developed generalized fluid-particle hybrid numerical code that can treat fluid electrons and ions, and an arbitrary number of kinetic species, including energetic particles. We discuss the structure of quasi-perpendicular shocks obtained in a standard hybrid simulation model with fluid electrons and kinetic ions. We show results of large-scale 2D simulations for the range of parameters, such as the plasma beta, the magnetic field obliquity angle, and the shock Mach number, including subcritical and supercritical conditions.