Absence of geomagnetic conjugacy in pulsating auroras

We have examined the geomagnetic conjugacy of pulsating auroras using TV camera data obtained simultaneously at Syowa in Antarctica and at Tjornes in Iceland. In order to exclude the magnetic field mapping problem, we investigated a period during which conjugate points were unambiguously identified from large-scale discrete conjugate auroras. The conjugacy of pulsating auroras revealed in this study may be summarized as follows. Some pulsating auroras appear in both hemispheres, while others appear only in one hemisphere. Even in the former case, the shape of the auroral form is generally different between the two hemispheres, and there is little or no interhemispheric correlation in the intensity variations. We could not find a pulsating aurora that appeared synchronously at the two endpoints of a flux tube. From these observational results and the increasing amount of evidence in recent studies, we conclude that the conjugacy of pulsating auroras is generally poor.