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The effects of an interplanetary shock on the high-latitude ionospheric convection during an IMF By-dominated period
Language
English
Obiettivo Specifico
2A. Fisica dell'alta atmosfera
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/26 (2008)
Pages (printed)
2937– 2951
Issued date
2008
Abstract
On 6 January 1998 an interplanetary shock hit
the magnetosphere around 14:15 UT and caused a reconfiguration
of the northern high-latitude ionospheric convection.
We use SuperDARN, spacecraft and ground magnetometer
data to study such reconfiguration. We find that the
shock front was tilted towards the morning flank of the magnetosphere,
while the Interplanetary Magnetic Field (IMF)
was By-dominated, with By<0, IMF Bz>0 and |By|>>Bz.
As expected, the magnetospheric compression started at the
first impact point of the shock on the magnetopause causing
an increase of the Chapman-Ferraro current from dawn
to dusk and yielding an increase of the geomagnetic field
at the geostationary orbit and on the ground. Moreover,
the high-latitude magnetometer data show vortical structures
clearly related to the interaction of the shock with the
magnetosphere-ionosphere system. In this context, the SuperDARN
convection maps show that at very high latitudes
above the northern Cusp and in the morning sector, intense
sunward convection fluxes appear, well correlated in time
with the SI arrival, having a signature typical for Bz>0 dominated
lobe reconnection. We suggest that in this case the dynamic
pressure increase associated to the shock plays a role
in favouring the setting up of a new lobe merging line albeit
|By|>>Bz>0.
the magnetosphere around 14:15 UT and caused a reconfiguration
of the northern high-latitude ionospheric convection.
We use SuperDARN, spacecraft and ground magnetometer
data to study such reconfiguration. We find that the
shock front was tilted towards the morning flank of the magnetosphere,
while the Interplanetary Magnetic Field (IMF)
was By-dominated, with By<0, IMF Bz>0 and |By|>>Bz.
As expected, the magnetospheric compression started at the
first impact point of the shock on the magnetopause causing
an increase of the Chapman-Ferraro current from dawn
to dusk and yielding an increase of the geomagnetic field
at the geostationary orbit and on the ground. Moreover,
the high-latitude magnetometer data show vortical structures
clearly related to the interaction of the shock with the
magnetosphere-ionosphere system. In this context, the SuperDARN
convection maps show that at very high latitudes
above the northern Cusp and in the morning sector, intense
sunward convection fluxes appear, well correlated in time
with the SI arrival, having a signature typical for Bz>0 dominated
lobe reconnection. We suggest that in this case the dynamic
pressure increase associated to the shock plays a role
in favouring the setting up of a new lobe merging line albeit
|By|>>Bz>0.
Type
article
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