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Lazarus, A. J.
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- PublicationOpen AccessGeomagnetic field variations at low and high latitude during the January 10-11, 1997 magnetic cloud(1998-07-15)
; ; ; ; ; ; ; ; ; ; ;Villante, U.; Dipartimento di Fisica, Università dell'Aquila, L'Aquila, Italy ;Francia, P.; Dipartimento di Fisica, Università dell'Aquila, L'Aquila, Italy ;Lepidi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;De Lauretis, M.; Dipartimento di Fisica, Università dell'Aquila, L'Aquila, Italy ;Pietropaolo, E.; Dipartimento di Fisica, Università dell'Aquila, L'Aquila, Italy ;Cafarella, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;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.; Lab. for Extraterrestrial Physics, NASA/GSFC, Greenbelt, USA ;Mariani, F.; Dipartimento di Fisica, Università di Roma-Tor Vergata, Italy; ; ; ; ; ; ; ; ; On Jan. 10-11, 1997 a wide magnetic cloud reached the Earth triggering intense geomagnetic activity. Observations performed at low and very high latitude show that the same features appear simultaneously in correspondence to different changes in the solar wind conditions. In particular, highly polarized modes are simultaneously observed at the same discrete frequencies after the passage of the high density solar wind region following the cloud. SI's and ULF waves polarization are also examined in a wide latitudinal and longitudinal extent.346 145 - PublicationRestrictedThe Earth's passage of the April 11, 1997 coronal ejecta: geomagnetic field fluctuations at high and low latitude during northward interplanetary magnetic field conditions(1999)
; ; ; ; ; ; ;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; ; ; ; ; 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.291 35