Quick magnetic reconnection triggering in an ion-scale current sheet: Transition from Type-I to Type-II

The details of Quick Magnetic Reconnection Triggering (QMRT) in ion-scale current sheets have been investigated using three-dimensional (3-D) full particle simulations with the mass ratio of 400. QMRT is mediated by coupling to the Lower-Hybrid Drift Instability (LHDI) and its time scale is as quick as the LHDI time scale. Up to the initial half-thickness D of D/lambda(i) = 0.875 (lambda(i): the ion inertial length), QMRT is attained via thin current layer formation at the center of the current sheet in reaction to the LHDI activity (Type-I). At D/lambda(i) = 1, QMRT is still available but is attained by boosting up the tearing instability growth rate via the electron temperature anisotropy T-e perpendicular to/T-e parallel to similar to 1.2 (Type-II). In this case the LHDI activity induces the current density redistribution that does not result in enhanced current density at the center but produces electron perpendicular heating therein.