Collisional effects on relativistic magnetic reconnection

In extreme astrophysical environments around compact objects such as neutron stars and black holes, magnetic reconnection is expected to occur in the relativistic magnetically dominated regime, where the magnetization σ >> 1. These regimes have previously been studied using particle-in-cell (PIC) simulations showing hard power-law spectra, that can help to explain radiation spectra. While kinetic simulations are typically small-scale and collisionless, in realistic astronomical scales, collisional effects also should play a role. In this study, we reproduce the hard power-laws using 2D PIC simulations, and investigate the effects of Coulomb collisions which are taken into account self-consistently using Monte Carlo methods. A large body of research has investigated how the spectra is generated via reconnection in such relativistic systems, but the mechanism remains under debate. Understanding the differences in the energetic particle spectra at large collisional scales, may help shed light on this debate, and provide more accurate spectra to compare with astronomical observations.