부산대학교 도서관

High sensitive TV observations of auroras were made together with ULF and VLF measurements at Ny Ålesund (75.4°, 131.4° geomagnetic coordinates), Svalbard in December-January, 1984-85 and 1985-86, in order to examine characteristics of dayside auroras and associated upper atmosphere phenomena. In this report we will discuss relationships between impulsive pulsation bursts in the Pc1 range and auroral displays near the dayside cusp region. The cusp region is characterized by the appearance of Pi-like bursts during daytime. These bursts have an enhancement band in the frequency of 0.3-0.8Hz. Pulsation bursts in the Pc1 range are often associated with occurrence of poleward moving auroras. Poleward drifts of auroral forms generally last for 1-3 minutes over spatial extent of 100-300km at ionospheric level. Poleward drifts of luminosity occasionally show a quasi-periodic repetition in a time scale of several minutes. One-to-one correspondence is often noted between the enhancement band in the Pc1 range and poleward movements of auroras having a duration of several minutes. Implication of these results is discussed in relation to observations of flux transfer events near the magnetopause.