Publication Date:
2019-12-05
Description:
We present an analysis of ULF geomagnetic field
fluctuations at low latitudes during the first CAWSES campaign
(29 March–3 April 2004). During the whole campaign,
mainly in the prenoon sector, a moderate Pc3-4 pulsation activity
is observed, clearly related to interplanetary upstream
waves. On 3 April, in correspondence to the Earth’s arrival of
a coronal mass ejection, two SIs are observed whose waveforms
are indicative of a contribution of the high-latitude
ionospheric currents to the low-latitude ground field. During
the following geomagnetic storm, low frequency (Pc5) waves
are observed at discrete frequencies. Their correspondence
with the same frequencies detected in the radial components
of the interplanetary magnetic field and solar wind speed suggests
that Alfv´enic solar wind fluctuations may act as direct
drivers of magnetospheric fluctuations. A cross-phase
analysis, using different pairs of stations, is also presented
for identifying field line resonant frequencies and monitoring
changes in plasmaspheric mass density. Lastly, an analysis
of ionospheric vertical soundings, measured at the Rome
ionosonde station (41.8 N, 12.5 E), and vertical TEC measurements
deduced from GPS signals within an European
network shows the relation between the ULF resonances in
the inner magnetosphere and thermal plasma density variations
during geomagnetically quiet conditions, in contrast to
various storm phases at the end of the CAWSES campaign.
Description:
Published
Description:
1455–1468
Description:
open
Keywords:
Magnetospheric physics
;
04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Format:
882721 bytes
Format:
application/pdf
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