We perform a one-dimensional full particle-in-cell (PIC) simulation of a quasi-parallel collisionless shock with Alfvén Mach number 6.6 and the shock angle 20 degrees between the upstream magnetic field and the shock normal direction. The FAB far upstream is generated by a reflection of incoming ions at the shock. They excite a right-handed Alfvén wave in the plasma rest frame through resonant beam instability. Both pitch-angle and energy diffusions of the FAB take place, as one approaches the shock. The maximum energy of the FAB near the shock is about 10 times larger than the energy in which the specular reflection at the shock is assumed. Nonlinear phase bunches of the FAB and the background ions are found near the shock due to the resonant and non-resonant trappings by the excited wave, respectively.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics