Magnetic islands formed due to the Kelvin-Helmholtz instability in the outflow region of collisionless magnetic reconnection

摘要

We carry out large-scale particle-in-cell kinetic simulations to demonstrate that a super-Alfvenic electron shear flow across the current layer can be spontaneously generated in the outflow region of magnetic reconnection, which is unstable to the electron Kelvin-Helmholtz (K-H) instability. The resulted K-H vortex structures continuously drive the secondary magnetic reconnection and formation of secondary magnetic islands, which leads to strong electron energization in the outflow region.