Princeton University Summer Astrophysics Colloquia

Kinetic plasma physics is an integral, but often neglected, component of many high-energy astrophysical systems. Understanding the dynamics and energization processes in collisionless plasmas is essential for interpreting the observable radiation spectra, luminosities, and variability of systems such as pulsar wind nebulae, accretion flows onto compact objects, and relativistic jets from active galactic nuclei. Kinetic turbulence has long been proposed as a primary process for energizing these collisionless plasmas, but questions remain as to its viability for producing nonthermal particle populations in various physical regimes. Particle-in-cell (PIC) simulations have recently opened this rich topic to detailed, first-principles numerical and theoretical scrutiny. I will overview recent progress on understanding particle energization in relativistic (and trans-relativistic) plasma turbulence, spurred by PIC simulations, including the demonstration of phenomena such as nonthermal particle acceleration, electron-ion thermal decoupling, and intermittent beaming of radiation. These new insights have applications for modeling various high-energy astrophysical systems.