Drift of auroral absorption observed in February 1986 with the scanning beam riometer at Syowa Station

• Main Authors: Takashi Kikuchi, Hisao Yamagishi
• Format: Report
• Language: English
• Published: Hiraiso Solar-Terrestrial Research Center, Communications Research Laboratory/National Institute of Polar Research 1990
• Subjects: Syowa Station; Antarc*; Antarctica
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=4081; http://id.nii.ac.jp/1291/00004081/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4081&item_no=1&attribute_id=18&file_no=1

The scanning beam riometer at Syowa Station, Antarctica (66.1°inv. lat.) detected drift of auroral absorptions during a severe geomagnetic storm in February 1986. Eastward drifts predominated in the morning sector (0600-0930 MLT) on February 8,1986,with speeds ranging from 1.0 to 3.8km/s. These drift velocities are considerably greater than those (60-700m/s) obtained under a moderately disturbed condition reported by T. KIKUCHI et al. (Ann. Geophys., 8,431,1990) while the drift direction was the same for both cases. The eastward drift takes place with a decrease in the geomagnetic H-component, with its speed being proportional to the H-component deflection from the quiettime level. It is suggested that both the absorption drift and ionospheric currents are subjected to a common earthward electric field in the magnetosphere. Therefore, the high drift velocity may indicate an intensification of the electric field in the magnetosphere.