In collisionless space plasmas, the two-scale (ion and electron) diffusion region plays an important role in reconnection physics. Within the ion diffusion region, the Hall signatures, resulting from the decoupling motions between ions and electrons, are the quadrupolar Hall magnetic field and the bipolar Hall electric field as well. In this talk, observational evidences of the Hall electromagnetic field for a reconnection event seen by Cluster spacecraft in the Earth’s magnetotail are presented. Further, I will introduce a newly developed reconstruction method, which is used to produce steady, two-dimensional field and plasma maps of the structure seen by a single spacecraft in the diffusion region. By using this reconstruction method, it is evident that the Hall current loops are responsible for generating the out-of-plane Hall magnetic field for reconnection. More interesting results from the maps are also discussed. In the end, I will briefly talk about my future research plans.
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