Magnetic reconnection between an emerging active region and the quiet Sun

Using the Solar Dynamics Observatory observations, we study the evolution of an emerging active region (EAR) and its reconnection with the quiet Sun. The EAR continuously interacts with the surrounding quiet region, and dark ribbons at the boundary of the EAR and the quiet Sun are observed. The extreme-ultraviolet observations show that the regions swept by the dark ribbons are brightened and the temperature increases. These results reveal that there exists an uninterrupted magnetic reconnection between the EAR and the quiet region and the released energy heats the corona of the quiet Sun. The dark ribbons are suggested to correspond to the interface of the reconnected fields and the undisturbed ones. The dark ribbon propagates outward, and this phenomenon is considered as a dark wave.