Outstanding Questions and Future Research of Magnetic Reconnection

This short article highlights the unsolved problems of magnetic reconnection in collisionless plasma.  The advanced in-situ plasma measurements and simulations enabled scientists to gain a novel understanding of magnetic reconnection.  Still, outstanding questions remain on the complex dynamics and structures in the diffusion region, on the cross-scale and regional couplings, on the onset of magnetic reconnection, and on the details of energetics.  Future directions of the magnetic reconnection research in terms of new observations, new simulations and interdisciplinary approaches are discussed.