Overview of the quiet-Sun coronal regions we analyzed and the underlying surface magnetic fields. A closer view of the coronal regions, outlined by white boxes in Fig. 1, is presented in the top panels. The field of view is 614″ × 614″. The red contours outline spatial locations of EUV bursts in the respective panels at that instance. The bottom panels show the line-of-sight magnetic field maps observed with SDO/HMI in grayscale. They are cotemporal with respect to the top panels, which are overlaid with red contours. The maps are saturated at ±50 G. The dark shaded regions represent south or negative-polarity magnetic field patches, and the light shaded regions represent north or positive-polarity magnetic field patches. The blue and green contours cover positive- and negative-polarity magnetic patches, respectively, with flux densities above 50 G. See Sects. 2, 3.1, and 3.2 for details.