Ground observations and possible source regions of two types of Pc 1-2 micropulsations at very high latitudes

• Published in: Journal of Geophysical Research 1997-12, Vol.102 (A12), p.11
• Main Authors: Dyrud, L P, Engebreston, M J, Posch, J L, Hughes, W J, Fukunishi, H, Arnoldy, R L, Newell, P T, Horne, R B
• Format: Article
• Language: English
• ISSN: 0148-0227

We have used one-year's data from the recently installed Magnetometer Array for Cusp and Cleft Studies (MACCS) in Arctic Canada and from two stations of the developing 'conjugate' array of Automated Geophysical Observatories (AGOs) in Antarctica to study ULF waves in the Pc 1-2 frequency band at cusp and polar cap latitudes (Lambda = 74-80 deg). In this paper we focus on the spectral properties and latitudinal and local time distributions of Pc 1-2 events observed during 1994 and use these along with several case studies to infer the source locations of the two major wave types we have observed. We found little variation in center-band frequency of the Pc 1-2 waves we observed, but the average event bandwidth was distinctly wider at stations near 80 MLAT than at stations near 75 MLAT. Broadband waves, with diffuse spectral character, dominated at the higher latitudes, but their occurrence was confined at most stations to within four hours of local magnetic noon. Waves with narrower bandwidth were much more common in our data set, and were the statistically dominant wave type at the lower-latitude MACCS stations. (Author)