Latitudinal features of cosmic noise absorption at the time of SSC-triggered substorm as observed with scanning beam riometer

• Main Authors: Takashi Kikuchi, Hisao Yamagishi
• Format: Report
• Language: English
• Published: Hiraiso Solar-Terrestrial Research Center, Communications Research Laboratory/National Institute of Polar Research 1989
• Subjects: Syowa Station; Antarc*; Antarctica
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=4059; http://id.nii.ac.jp/1291/00004059/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4059&item_no=1&attribute_id=18&file_no=1

The scanning beam riometer at Syowa Station, Antarctica (Inv. Lat.=66.1°) detected spatial and temporal variations of the precipitation of energetic electrons responsible for the cosmic noise absorption (CNA) associated with the storm sudden commencement (SSC) at 2353 UT, November 3,1986 and the subsequent substorm. The SSC-associated precipitation was restricted equatorward of Syowa Station, while the substorm-associated precipitation started equatorward and was displaced poleward with stronger intensity at higher latitudes. It is deduced that the SSC-associated precipitation shifted equatorward at a speed of 500m/s, while the substorm-associated precipitation rapidly poleward at a speed of 5.8km/s. These results clearly indicate two kinds of energetic electrons associated with the SSC-triggered substorm. Particularly, the latitudinal feature of precipitation indicates that the energetic electrons associated with an SSC originate in the trapped radiation belt, which are forced to precipitate by a hydromagnetic shock propagated from the magnetopause.