Shock-mediated kinetic turbulence

Turbulence with sufficiently strong and compressive driving is prone to developing intermittent shocks, which may mediate the energy cascade and dissipation. While studied extensively in the collisional fluid regime, the basic properties of shock-mediated turbulence remain poorly understood in collisionless plasmas. We describe new theoretical and numerical results on shock-mediated kinetic turbulence, leveraging two-dimensional particle-in-cell (PIC) simulations in the transsonic and relativistic regime, where the sound speed is a significant fraction of the speed of light. The PIC simulations form an ensemble of perpendicular fast-mode shocks that interact, trigger secondary instabilities, and accelerate nonthermal particles to high energy. We study the shock fronts in detail to better understand their nature. The results may be relevant for modeling nonthermal radiative emission in high-energy astrophysical systems such as relativistic jets from black holes.