A Model of Magnetic Pi 2 Pulsations Based on a ULF Obserbation from High- to Middle-Latitudes (d. ULF Waves in the Magnetosphere) (Proceedings of the Second Symposium on Coordinated Observations of the Ionosphere and Magnetosphere in the Polar Regions : Part I)

• Published in: Nankyoku shiryo no. 68
• Main Author: Masayuki KUWASHIMA
• Format: Journal Article
• Language: English
• Published: National Institute of Polar Research 01.02.1980
• ISSN: 0085-7289; 2432-079X
• DOI: 10.15094/00008135

Spectral characteristics of magnetic Pi 2 pulsations are studied in detail by using data obtained simultaneously over a wide latitudinal range from the auroral region (L=8.9) through low-latitudes (L=1.8). Pi 2 is observed simultaneously with the onset of a substorm expansion over the wide latitudinal range with a common predominant period showing a primary amplitude maximum at the auroral oval and a secondary one near the plasmapause. The Pi 2 period generally becomes shorter (longer) when the associated auroral breakup starts at lower (higher) latitudes. Pi 2 is also observed simultaneously at a pair of conjugate stations in the auroral region with similar waveforms. These observational results indicate that the most plausible model of Pi 2 is the torsional hydromagnetic oscillation of the geomaenetic field lines anchored on the auroral oval.