Unraveling Coherent Structures in Relativistic Turbulence: Insights from PIC Simulations and Intermittency Analysis

Relativistic turbulence, which occurs within a plasma where magnetic energy dominates the internal energy, is often associated with high-energy astronomical sources and can efficiently accelerate relativistic particles. Traditionally, an analytical understanding of this acceleration has been achieved through quasi-linear theory (QLT). However, recent particle-in-cell (PIC) simulations have revealed that QLT fails to account for anisotropy, reproduce the particle distribution observed in PIC simulations, or accurately describe current sheet acceleration. These inconsistencies are believed tobe related to the coherent structures observed in PIC simulations.

To enhance our understanding of coherent structures in relativistic turbulence, we analyze PIC simulations to investigate the properties of current sheets and other coherent structures. We explore a range of magnetization and magnetic fluctuation strengths, map out the dissipative structures, determine their fractal dimensionality, and examining their relationship with She-Leveque-like intermittency. Notably, our analysis uncovers a significant finding through modeling the current sheet distribution as a fractal, enabling the measurement of the filling factor. Subsequently, we explore the derived relationships between intermittency models and plasma parameters, culminating in a discussion on the potential impact of these findings on current acceleration theories.