Fast-shear-flow generated multiple magnetic islands and Alfvénic resonance layers in magnetic reconnection

Abstract

Abstract Magnetic reconnection in the presence of fast sheared plasma flows is investigated using two-dimensional incompressible resistive MHD simulation. It is found that if the initial shear-flow velocity is sufficiently large, multiple Alfvén resonance layers can be formed in the inflow region away from the reconnection separatrices. In particular, two Alfvén layers are formed when the initial asymptotic flow velocity is twice the Alfvén velocity. The Alfvén layers are located in the narrow regions where the flow speed equals or twice the local Alfvén speed. The formation and evolution of the Alfvén layers and magnetic islands are analyzed. It is suggested that the geometry of the magnetic field lines during the islands complex inosculated process is related to the local distribution of velocities. The results may be applied to where the magnetic reconnection occurs with large plasma shear flows in laboratory and space plasma.