The Earth's passage of the April 11, 1997 coronal ejecta: geomagnetic field fluctuations at high and low latitude during northward interplanetary magnetic field conditions

• Main Authors: Lepidi, S., Francia, P., Villante, U., Meloni, A., Lazarus, A. J., Lepping, R. P.
• Other Authors: Lepidi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Francia, P.; Dipartimento di Fisica, Università dell'Aquila, L'Aquila, Italy, Villante, U.; Dipartimento di Fisica, Università dell'Aquila, L'Aquila, Italy, Meloni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Lazarus, A. J.; Center for Space Research, MIT, Cambridge, USA, Lepping, R. P.; Laboratory for Extraterrestrial Physics, NASA/GSFC, Greenbelt, USA, Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Dipartimento di Fisica, Università dell'Aquila, L'Aquila, Italy, Center for Space Research, MIT, Cambridge, USA, Laboratory for Extraterrestrial Physics, NASA/GSFC, Greenbelt, USA
• Format: Article in Journal/Newspaper
• Language: English
• Published: EGS - Springer-Verlag 1999
• Subjects: Magnetospheric physics; MHD waves and instabilities; Solar wind-magnetosphere interactions; 01. Atmosphere::01.03. Magnetosphere::01.03.99. General or miscellaneous; 01. Atmosphere::01.03. Magnetosphere::01.03.04. Structure and dynamics; Antarctic; Terra Nova Bay; Antarc*
• Online Access: http://hdl.handle.net/2122/3934

An analysis of the low frequency geomagnetic field fluctuations at an Antarctic (Terra Nova Bay) and a low latitude (L'Aquila, Italy) station during the Earth's passage of a coronal ejecta on April 11, 1997 shows that major solar wind pressure variations were followed at both stations by a high fluctuation level. During northward interplanetary magnetic field conditions and when Terra Nova Bay is close to the local geomagnetic noon, coherent fluctuations, at the same frequency (3.6 mHz) and with polarization characteristics indicating an antisunward propagation, were observed simultaneously at the two stations. An analysis of simultaneous measurements from geosynchronous satellites shows evidence for pulsations at approximately the same frequencies also in the magnetospheric field. The observed waves might then be interpreted as oscillation modes, triggered by an external stimulation, extending to a major portion of the Earth's magnetosphere. Published 1245-1250 N/A or not JCR reserved