First-principles demonstration of diffusive-advective particle acceleration in kinetic simulations of relativistic plasma turbulence

Understand

Nonthermal relativistic plasmas are ubiquitous in astrophysical systems like pulsar wind nebulae and active galactic nuclei, as inferred from their emission spectra.

• The underlying nonthermal particle acceleration (NTPA) processes have traditionally been modeled with a Fokker-Planck (FP) diffusion-advection equation in momentum space.
• In this paper, we directly test the FP framework in ab-initio kinetic simulations of driven magnetized turbulence in relativistic pair plasma.
• By statistically analyzing the motion of tracked particles, we demonstrate the diffusive nature of NTPA and measure the FP energy diffusion ($D$) and advection ($A$) coefficients as functions of particle energy $\gamma m_e c^2$.