Characterizing Relativistic Fast Mode Cascade in 2D Kinetic Turbulence

Two-dimensional (2D) wave turbulence has been widely studied, culminating in a variety of analytical models, but remains largely computationally unexplored in the relativistic, collisionless plasma regime. To address this, we present results from particle-in-cell (PIC) simulations of driven 2D relativistic turbulence in a pair plasma. In this regime, relativistic magnetohydrodynamic fast modes are expected to mediate energy transfer across scales. Using spatiotemporal Fourier analysis, we identify the presence and influence of fast modes in the turbulent cascade. We further explore how the properties of the turbulence vary across a range of plasma beta values and driving amplitudes. These findings provide insight into the structure of relativistic wave turbulence and may have implications for entropy production and non-thermal particle acceleration mechanisms in high-energy astrophysical environments such as relativistic jets and pulsar wind nebulae.