Hybrid modeling of diffusive shock acceleration in collisionless shocks in multispecies plasma

J. A. Kropotina, A. M. Bykov, V. E. Ermolina, S. M. Osipov, V. I. Romansky
2018 Communications of the Byurakan Astrophysical Observatory  
Diffusive shock acceleration (DSA) is a very efficient mechanism of high energy particle acceleration in heliosphere, supernova remnants, stellar winds and gamma-ray bursts. We present microscopic simulation of particle injection and diffusive shock acceleration which is performed with 3D divergence-conserving second-order accurate hybrid code "Maximus". Hydrogen plasma with admixture of various heavy ions is considered. The injection process is found to start through shock reflection for both
more » ... ydrogen and heavier ions. However, the reflection process depends on charge-to-mass ratio. While hydrogen ions reflection appears at shock ramp and is governed by the cross-shock potential, the reflection of ions with greater A=Z proceeds deeper down-stream via gyration in perpendicular magnetic field component. The heavy ions appear to inject into the DSA preferentially, but this chemical enhancement saturates with growing A=Z. The protons injection efficiency is estimated within various approaches, and it is shown that about 20% of initial flow energy goes into accelerated particles.
doi:10.52526/25792776-2018.2.2-373 fatcat:oewh2wapmvevhdyevxs77ad2oe