Energy conversion and magnetization scaling in relativistic magnetohydrodynamic magnetic reconnection

Relativistic magnetic reconnection occurs in plasmas with a strong magnetization parameter (ratio of magnetic to rest mass energy density). We study this reconnection by employing relativistic resistive magnetohydrodynamics simulations. Starting with a Harris sheet configuration, we calculate reconnection rates at varying magnetic Reynolds numbers to validate the Sweet-Parker scaling. The magnetic energy dissipation is initially dominated by resistive electric field but the convective electric field gradually becomes the dominant contributor. The plasma primarily gains energy from regions within the current sheet and near the separatrix. We perform scans of the magnetization parameter from medium to large values. The scaling of the reconnection rate with the magnetization parameter is weaker than theoretical predictions. We find that this is due to conversion of magnetic energy mostly into thermal energy, leading to strong compressibility. The scaling of the compressiblity factor is calculated and verified, providing a more accurate representation of inflow dynamics in this regime. By adding and varying a guide field, we find that a stronger guide field reduces the reconnection rate but shows minimal impact on the relative partition of kinetic, magnetic, and thermal energy in the outflow, with thermal energy consistently dominating at nearly 90%. This work contributes towards understanding energy conversion mechanisms in high-energy astrophysical plasmas.