Electron Behavior Around the Onset of Magnetic Reconnection

We investigate the onset of magnetic reconnection, utilizing a fully kinetic Particle‐In‐Cell (PIC) simulation. Characteristic features of the electron phase‐space distributions immediately before reconnection onset are identified. These include signatures of pressure non‐gyrotropy in the velocity distributions, and lemon shaped distributions in the in‐plane velocity directions. Further, we explain how these features form through particle energization by the out‐of‐plane electric field. Identification of these features in the distributions can aid in analysis of data where clear signatures of ongoing reconnection are not yet present. In any environment where magnetic fields and charged particles interact, magnetic reconnection will occur if the conditions are favorable. Magnetic reconnection can be described as magnetic explosions, since it releases stored magnetic energy and converts it into heat and movement of the plasma particles. In this paper, we use numerical simulations to take a closer look at how the reconnection process initiates, a fundamental question still not fully understood. Signatures indicating reconnection onset can be identified in the electron distributionsOnset signatures persist over extended spatial and temporal scalesThe particle distributions immediately preceding onset are characterized by features of non‐gyrotropy and acceleration Signatures indicating reconnection onset can be identified in the electron distributions Onset signatures persist over extended spatial and temporal scales The particle distributions immediately preceding onset are characterized by features of non‐gyrotropy and acceleration