How Hall Electric Fields Intrinsically Chaotize And Heat Ions During Collisionless Magnetic Reconnection

The origin of extreme and anomalous ion heating during magnetic reconnection has been a long-standing mystery. It is shown in this paper that, at the core of the process, the stochastic heating mechanism is responsible for this energization. The in-plane Hall electric fields that intrinsically develop during collisionless reconnection not only accelerate ions but also thermalize them by inducing chaotic motion. The mechanism explains various observed features of ion heating, e.g., its relation to the guide field strength and the ion mass-to-charge ratio.