Hybrid particle-in-cell modeling of astrophysical plasmas

A second-order accurate divergence-conserving hybrid particle-in-cell code Maximus has been developed for microscopic modeling of collisionless plasmas. The main specifics of the code include a constrained transport algorithm for exact conservation of magnetic field divergence, a Boris-type particle pusher, a weighted particle momentum deposit on the cells of the 3d spatial grid, an ability to model multispecies plasmas, and an adaptive time step. The code is efficiently parallelized for running on supercomputers by means of the message passing interface (MPI) technology. A detailed description of the developed approach can be found in two dedicated papers published in Technical Physics: Hybrid simulation of collisionless shock waves in space plasmas and Relaxation of heavy ions in collisionless shock waves in cosmic plasmas.

A video illustration of the results obtained with Maximus shows first order Fermi acceleration of protons (white circles) and He(+2) ions by a proton-dominated quasiparallel supercritical collisionless shock. The proton phase space evolution is shown together with accelerated particles positions. The ions injection via shock reflection and subsequent energy gain during multiple scattering upstream and downstream is visible.