Monochromatic auroral images observed at Syowa Station, in Antarctica.

Abstract

A new TV camera system was developed for monochromatic digital imaging of auroras. On the basis of observation in 1984 at Syowa Station, Antarctica by the TV system, three types of auroral activities were analysed, i. e., i) stable auroras in the dusk sector, ii) active auroras and iii) pulsating auroras in the dawn sector. The results are; 1) diffuse auroral belt which appears at the lower latitude border of auroral activity coincides with the distribution of Hβ emission, 2) enhancement of auroral 5577Å emission is much larger than that of 6300Å emission at the westward travelling surge and 3) period of auroral pulsation in the dawn sector shows regional variations. The observation suggests; 1) that the diffuse aurora in the dusk sector at the lower latitude side is excited by auroral protons, 2) that a hardening of energy spectrum of precipitating electron is associated with the westward travelling surge.