Electron and Proton Acceleration in Trans-Relativistic Magnetic Reconnection: Dependence on Plasma Beta and Magnetization

Understand

Non-thermal electron acceleration via magnetic reconnection is thought to play an important role in powering the variable X-ray emission from radiatively inefficient accretion flows around black holes.

• The trans-relativistic regime of magnetic reconnection, where the magnetization $\sigma$, defined as the ratio of magnetic energy density to enthalpy density, is $\sim 1$, is frequently encountered in such flows.
• By means of a large suite of two-dimensional particle-in-cell simulations, we investigate electron and proton acceleration in the trans-relativistic regime.
• We focus on the dependence of the electron energy spectrum on $\sigma$ and the proton $\beta$ (i.e., the ratio of proton thermal pressure to magnetic pressure).