Electron‐Only Reconnection as a Transition From Quiet Current Sheet to Standard Reconnection in Earth's Magnetotail: Particle‐In‐Cell Simulation and Application to MMS Data

Abstract

AbstractStandard magnetic reconnection couples with both electron‐ and ion dynamics. Recently, a new type of magnetic reconnection, electron‐only reconnection without the coupling of ion dynamics, has been observed in space. Using a two‐dimensional particle‐in‐cell simulation, we show that in the externally‐driven magnetotail, electron‐only reconnection is a transition from quiet current sheet to standard reconnection. We find that (a) energy conversion j ⋅ E′ is around zero in quiet current sheet but nonzero in electron‐only reconnection, and (b) ion temperature does not change across electron‐only reconnection but peaks at the center of standard reconnection. These two differences can be used as criteria to distinguish magnetotail electron‐only reconnection from quiet current sheet and standard reconnection, respectively. Based on the two criteria, we justify that the MMS 17 June 2017 event is a magnetotail electron‐only reconnection event.