Publication Date:
2022-06-15
Description:
The ionospheric response at middle and high latitudes
in the Antarctica American and Australian sectors
to the 26–27 September 2011 moderately intense geomagnetic
storm was investigated using instruments including
an ionosonde, riometer, and GNSS receivers. The multiinstrument
observations permitted us to characterize the
ionospheric storm-enhanced density (SED) and tongues of
ionization (TOIs) as a function of storm time and location,
considering the effect of prompt penetration electric fields
(PPEFs). During the main phase of the geomagnetic storm,
dayside SEDs were observed at middle latitudes, and in the
nightside only density depletions were observed from middle
to high latitudes. Both the increase and decrease in ionospheric
density at middle latitudes can be attributed to a combination
of processes, including the PPEF effect just after
the storm onset, dominated by disturbance dynamo processes
during the evolution of the main phase. Two SEDs–TOIs
were identified in the Southern Hemisphere, but only the first
episode had a counterpart in the Northern Hemisphere. This
difference can be explained by the interhemispheric asymmetry
caused by the high-latitude coupling between solar wind
and the magnetosphere, which drives the dawn-to-dusk component
of the interplanetary magnetic field. The formation
of polar TOI is a function of the SED plume location that
might be near the dayside cusp from which it can enter the
polar cap, which was the case in the Southern Hemisphere.
Strong GNSS scintillations were observed at stations collocated
with SED plumes at middle latitudes and cusp on the
dayside and at polar cap TOIs on the nightside.
Description:
Published
Description:
1113–1129
Description:
2A. Fisica dell'alta atmosfera
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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