A set of collisionless shocks in various astrophysical environments was simulated by means of the 3d hybrid code "Maximus". Several tasks concerning supernovae reverse and forward shocks, intracluster merger shocks and the Earth's bow shock were solved. General results are the following:

1. The injection of hydrogen into the 1st order Fermi acceleration process is suppressed in supernovae reverse shocks with high metallicity. This is likely due to the shock front broadening and growth of characteristic wavelengths and periods because of heavy ions admixture.
2. Distributions of small admixture of heavy weakly charged ions downstream quasi-perpendicular collisionless shocks are highly anisotropic and non-maxwellian. Their relaxation proceeds slowly via alfven-ion-cyclotron instability, but still takes place on collisionless scales. Ions postshock temperatures are nearly mass-proportional, with small underheating of heavy ions.
3. Diffusion law of suprathermal particles is bohm-like just ahead of the shock and matches the quasi-linear theory further upstream. The criteria of applicability of different diffusion laws are estimated.
4. The shape of iron postshock distributions during galaxy clusters merger depends on helium abundance. This gives a chance to constrain plasma chemical composition by means of refined spectroscopy of the next generation.
5. A current density of rotational discontinuities crossing the Earth's bow shock is amplified. This amplification weakly depends on the shock Mach number or inclination, but is highly boosted by the presence of suprathermal particles. The discontinuity sweeps accelerating particles to the shock, thus the Fermi acceleration process can be altered in case of multiple upstream discontinuities.

Page created on July 16, 2021.