The Role of Electron Acceleration in Quick Reconnection Triggering

Abstract

We have recently found a quick spontaneous triggering mechanism of magnetic reconnection in an ion-scale current sheet, in which electron acceleration plays a crucial role. In the quick triggering, the lower hybrid drift waves are first excited at the outer-edges of the current sheet. The non-linear evolution of the lower hybrid drift instability modifies the current density distribution and thus the magnetic field profile. It is the inductive electric field associated with this change in the magnetic structure that efficiently accelerates the meandering electrons around the magnetic neutral sheet. The accelerated electrons sustain the imbedded thin current layer that is also formed in response to the re-arrangement of the current density. Such a current layer is highly unstable to the tearing mode and thus is crucial for making the quick triggering available.