Characteristics of VLF Saucers Observed by ISIS-1, 2 Satellites

Characteristics of the saucer emissions are studied by using ISIS VLF data which were received at Syowa Station by the wintering party of the 17th Japanese Antarctic Research Expedition in 1976-1977. Saucers were observed most frequently in the nighttime in winter and were scarcely observed in summer, The magnetic latitude ranges in which saucers were observed are ～60゜-75° in the nighttime and ～70°-80゜ in the daytime. These occurrence regions are located at the higher latitude side of the plasmapause and at the lower latitude side of the hiss occurrence regions. The shapes of saucers on frequency-time spectra showed generally two different types,i e, symmetrical hyperbolic shapes and symmetrical V-shapes